How severe is GHSA-fc7x-2cmc-8j2g?

GHSA-fc7x-2cmc-8j2g has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by GHSA-fc7x-2cmc-8j2g?

GHSA-fc7x-2cmc-8j2g affects the following packages: sha2 (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-fc7x-2cmc-8j2g?

Update sha2 to 0.9.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fc7x-2cmc-8j2g is resolved across your whole dependency graph.

How do I detect GHSA-fc7x-2cmc-8j2g in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sha2. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-fc7x-2cmc-8j2g if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-fc7x-2cmc-8j2g?

O3 pinpoints whether GHSA-fc7x-2cmc-8j2g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-fc7x-2cmc-8j2g actively exploited in the wild?

No public exploit code has been indexed for GHSA-fc7x-2cmc-8j2g yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-fc7x-2cmc-8j2g?

GHSA-fc7x-2cmc-8j2g has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 52th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was GHSA-fc7x-2cmc-8j2g published, and has it been updated?

GHSA-fc7x-2cmc-8j2g was published on January 6, 2022 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

GHSA-fc7x-2cmc-8j2g

CRITICAL

Incorrect hash in sha2

Also known asCVE-2021-45696 GHSA-xpww-g9jx-hp8rRUSTSEC-2021-0100

Published

Jan 6, 2022

Updated

Nov 8, 2023

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk52th percentile+0.60%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🦀sha2

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

The v0.9.7 release of the sha2 crate introduced a new AVX2-accelerated backend which was automatically enabled for all x86/x86_64 CPUs where AVX2 support was autodetected at runtime.

This backend was buggy and would miscompute results for long messages (i.e. messages spanning multiple SHA blocks).

The crate has since been yanked, but any users who upgraded to v0.9.7 should immediately upgrade to v0.9.8 and recompute any hashes which were previously computed by v0.9.7.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`sha2`	≥ 0.9.7&&< 0.9.8	0.9.8

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sha2. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update sha2 to 0.9.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fc7x-2cmc-8j2g is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-fc7x-2cmc-8j2g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-fc7x-2cmc-8j2g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

The v0.9.7 release of the sha2 crate introduced a new AVX2-accelerated backend which was automatically enabled for all x86/x86_64 CPUs where AVX2 support was autodetected at runtime. This backend was buggy and would miscompute results for long messages (i.e. messages spanning multiple SHA blocks). The crate has since been yanked, but any users who upgraded to v0.9.7 should immediately upgrade to v0.9.8 and recompute any hashes which were previously computed by v0.9.7.

O3 Security · Impact-Aware SCA

Is GHSA-fc7x-2cmc-8j2g in your dependencies?

O3 detects GHSA-fc7x-2cmc-8j2g across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works