Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
🦀
🦀 crates.io
Not in CISA KEV
HIGH severity

Out of bounds write in stackvectorGHSA-9frf-r7c7-j2vg

HIGH

GHSA-9frf-r7c7-j2vg is a high-severity (CVSS 7.3) Out-of-bounds Write vulnerability in stackvector. 1 public exploit reference exists, so weaponization risk is real. A fix is available for stackvector — see the affected versions and patch details below.

Also known asCVE-2021-29939RUSTSEC-2021-0048
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-9frf-r7c7-j2vg.

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk
0.26%0.68%1.10%1.52%0.8%1.0%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-9frf-r7c7-j2vg by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🦀stackvector

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

StackVec::extend used the lower and upper bounds from an Iterator's size_hint to determine how many items to push into the stack based vector. If the size_hint implementation returned a lower bound that was larger than the upper bound, StackVec would write out of bounds and overwrite memory on the stack. As mentioned by the size_hint documentation, size_hint is mainly for optimization and incorrect implementations should not lead to memory safety issues.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iostackvectorall versions1.0.9cargo update -p stackvector --precise 1.0.9

Affected Products

1 product · 1 configurations
Application
stackvectorstackvector_project
< 1.0.9
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for stackvector, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update stackvector to 1.0.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9frf-r7c7-j2vg is resolved across your whole dependency graph.

  3. Workarounds

    Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

StackVec::extend used the lower and upper bounds from an Iterator's size_hint to determine how many items to push into the stack based vector. If the size_hint implementation returned a lower bound that was larger than the upper bound, StackVec would write out of bounds and overwrite memory on the stack. As mentioned by the size_hint documentation, size_hint is mainly for optimization and incorrect implementations should not lead to memory safety issues.
O3 Security · Impact-Aware SCA

Is GHSA-9frf-r7c7-j2vg in your dependencies?

Find it across crates.io, including transitive dependencies.

Out of bounds write in stackvector (High 7.3)