CVE-2026-25541

5.5 MEDIUM 0.6% exploit odds Fix listed Memory safety Library

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. High risk of service disruption.
Exploit odds: 0.6% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-02-04 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:24 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.6% in the next 30 days (EPSS).
Severity: 5.5 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-02-04 22:16 UTC
Last modified: 2026-06-17 10:24 UTC
Exploit probability: 0.6% · EPSS, next 30 days
Weakness: CWE-680
Record status: Analyzed

Affected

tokio-rs Bytes < 1.11.1

Attack profile CVSS 4.0 · 5.5

Attack vector: Local
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-25541.md and follow it. Check whether this project is affected by CVE-2026-25541. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record