Vulnerability Description
Bytes is a utility library for working with bytes. From version 1.2.1 to before 1.11.1, Bytes is vulnerable to integer overflow in BytesMut::reserve. In the unique reclaim path of BytesMut::reserve, if the condition "v_capacity >= new_cap + offset" uses an unchecked addition. When new_cap + offset overflows usize in release builds, this condition may incorrectly pass, causing self.cap to be set to a value that exceeds the actual allocated capacity. Subsequent APIs such as spare_capacity_mut() then trust this corrupted cap value and may create out-of-bounds slices, leading to UB. This behavior is observable in release builds (integer overflow wraps), whereas debug builds panic due to overflow checks. This issue has been patched in version 1.11.1.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Tokio-Rs | Bytes | >= 1.2.1, < 1.11.1 |
Related Weaknesses (CWE)
References
- https://github.com/tokio-rs/bytes/commit/d0293b0e35838123c51ca5dfdf468ecafee4398Patch
- https://github.com/tokio-rs/bytes/releases/tag/v1.11.1ProductRelease Notes
- https://github.com/tokio-rs/bytes/security/advisories/GHSA-434x-w66g-qw3rExploitVendor Advisory
- https://rustsec.org/advisories/RUSTSEC-2026-0007.htmlExploitThird Party Advisory
FAQ
What is CVE-2026-25541?
CVE-2026-25541 is a vulnerability with a CVSS score of 7.5 (HIGH). Bytes is a utility library for working with bytes. From version 1.2.1 to before 1.11.1, Bytes is vulnerable to integer overflow in BytesMut::reserve. In the unique reclaim path of BytesMut::reserve, i...
How severe is CVE-2026-25541?
CVE-2026-25541 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-25541?
Check the references section above for vendor advisories and patch information. Affected products include: Tokio-Rs Bytes.