vulnerability / NVI-00016367 / Revision 1
re2: Global `String.prototype.match` with an empty-matchable pattern never advances → infinite loop with unbounded native memory growth (DoS)
GitHub lists this reviewed advisory for re2. 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.
6.2 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
re2
source listed<= 1.25.1
## Summary `String.prototype.match` with a **global** `RE2` collects all matches in a native loop that advances the cursor by the match length. A **zero-width (empty) match** has length 0, so the cursor never advances: the same empty match is found forever and appended to an ever-growing native vector. Any pattern that can match the empty string (`a*`, `b?`, `x{0,3}`, `(a)|`, `(?:)`, …) therefore causes an infinite loop with unbounded memory growth. The call is synchronous native code, so it blocks the entire event loop and cannot be interrupted by `try/catch`, `AbortController`, `--max-old-space-size`, or timers — the process must be killed externally. This diverges from the built-in engine, where `'xxxx'.match(/a*/g)` returns a finite array. ## Root cause ```cpp // lib/match.cc:44 — global branch of WrappedRE2::Match while (re2->regexp.Match(str, byteIndex, str.size, anchor, &match, 1)) { groups.push_back(match); byteIndex = match.data() - str.data + match.size(); // += 0 for a zero-width match } ``` When `match.size() == 0`, `byteIndex` is unchanged, so the next iteration matches the same empty position again; `groups` grows without bound. The other iteration paths
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. GitHub Advisory Database
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.
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-6hxr-mr5r-9836 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.