CVE-2026-44983: smallbitvec: Safe API Triggered Heap Buffer Overflow via Integer Overflow

Severity: high (CVSS 7.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-26 · updated 2026-07-24
Weakness: CWE-122

Description

smallbitvec is a growable bit-vector for Rust, optimized for size. From 1.0.1 to 2.6.0, an integer overflow in the internal capacity calculation of smallbitvec can lead to an undersized heap allocation, resulting in a heap buffer overflow through safe APIs only. This allows memory corruption without requiring unsafe code from the caller. This vulnerability is fixed in 2.6.1.

Affected products

servo smallbitvec: from 1.0.1, < 2.6.1

References

https://github.com/servo/smallbitvec/security/advisories/GHSA-97wc-2hqc-cjgr
https://github.com/servo/smallbitvec/security/advisories/GHSA-97wc-2hqc-cjgr

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