vulnerability / NVI-00004730 / Revision 4
PHPSpreadsheet: XLS/OLE sector-chain self-loop causes memory exhaustion
GitHub lists this reviewed advisory for phpoffice/phpspreadsheet, phpoffice/phpspreadsheet, phpoffice/phpspreadsheet, phpoffice/phpspreadsheet, phpoffice/phpspreadsheet. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
7.5 HIGH (3.1)
security-advisories@github.com severity; no combined Null risk score.
0.461%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.40091. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
phpoffice/phpspreadsheet
source listed>= 4.0.0, <= 5.8.0
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listed>= 3.3.0, <= 3.10.6
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listed>= 2.2.0, <= 2.4.6
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listed>= 2.0.0, <= 2.1.17
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listed<= 1.30.5
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listedECOSYSTEM: introduced 4.0.0; fixed 5.8.1
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listedECOSYSTEM: introduced 3.3.0; fixed 3.10.7
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listedECOSYSTEM: introduced 2.2.0; fixed 2.4.7
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listedECOSYSTEM: introduced 2.0.0; fixed 2.1.18
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
phpoffice/phpspreadsheet
source listedECOSYSTEM: introduced 0; fixed 1.30.6
## Summary PhpSpreadsheet's OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed `.xls`/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, `OLERead::read()` appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from `Reader\Xls::canRead()` and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. ## Vulnerability details `OLERead::read()` loads the input and builds sector chains from attacker-controlled OLE header and allocation-table values: - `src/PhpSpreadsheet/Shared/OLERead.php:82` reads the entire file after validating only the OLE magic. - `src/PhpSpreadsheet/Shared/OLERead.php:84-97` reads sector-chain metadata from the file header. - `src/PhpSpreadsheet/Shared/OLERead.php:132-146` builds `bigBlockChain` and then follows the small-block depot chain. The vulnerable loop is: ```php $sbdBlock = $this->sbdStartBlock; $this->smallBlockChain = ''; while ($sbdBloc
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 5.8.1 for phpoffice/phpspreadsheet. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- vendor patch
The original advisory lists fixed boundaries 3.10.7 for phpoffice/phpspreadsheet. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- vendor patch
The original advisory lists fixed boundaries 2.4.7 for phpoffice/phpspreadsheet. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- vendor patch
The original advisory lists fixed boundaries 2.1.18 for phpoffice/phpspreadsheet. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- vendor patch
The original advisory lists fixed boundaries 1.30.6 for phpoffice/phpspreadsheet. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-xh5m-36r6-47m3 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-xh5m-36r6-47m3 ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-59933 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-59933 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 4 ·
Source facts changed; compare the preserved prior revision.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.