vulnerability / NVI-00013040 / Revision 3
Wire Swift runtime: negative LENGTH_DELIMITED length in skipGroup() crashes any protobuf-decoding service
GitHub lists this reviewed advisory for github.com/square/wire. 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.
0.690%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.52837. 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.
github.com/square/wire
source listed<= 6.4.0
### Summary Wire's Swift runtime (`Wire` SPM/CocoaPods product, implemented by `wire-runtime-swift`) did not reject a negative `LENGTH_DELIMITED` field length while skipping an unknown protobuf group. A crafted 10-byte protobuf payload could cause `ProtoReader.skipGroup()` to read a length-delimited field whose varint decodes to a negative `Int32`. That negative value was then passed to `ReadBuffer.readData(count:)`. `ReadBuffer` checked only that the requested read did not go past the end of the buffer. It did not reject negative counts. As a result, a negative count could pass the bounds check and reach Foundation's `Data(bytes:count:)`, which traps and aborts the process (`Signal 5` / SIGTRAP) instead of throwing Wire's documented `ProtoDecoder.Error`. This is the Swift sibling of the Kotlin/JVM negative-length-in-`skipGroup()` issue fixed in `com.squareup.wire:wire-runtime` 6.3.0 (`CVE-2026-45799`, `GHSA-7xpr-hc2w-34m9`). That earlier fix added a `length < 0` rejection to the Kotlin readers. The functionally similar Swift `ProtoReader.skipGroup()` path was not covered by that fix and remained vulnerable in released Swift runtime versions through `6.4.0`, and in Wire 7 alpha
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
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-86wm-r4c5-2rc9 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-61695 ↗
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-2026-61695 ↗
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 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.