CVE-2025-26519: musl libc 0.9.13 through 1.2.5 before 1.2.6 has an out-of-bounds write vulnerability when an attacker can trig

Routine

HIGH 8.1UPGRADE

CVE-2025-26519 is a high-severity flaw (CVSS 8.1) affecting musl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

musl libc 0.9.13 through 1.2.5 before 1.2.6 has an out-of-bounds write vulnerability when an attacker can trigger iconv conversion of untrusted EUC-KR text to UTF-8.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Local
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-787
Published	2025-02-14
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: musl-libc

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-02-14 04:15 UTCPublished CVE record published
2026-06-17 09:01 UTCUpdated Record last modified

musl-libc musl UPGRADE

Affected: >= 0.9.13 and < 1.2.6

Fixed in: 1.2.6

Safe to downgrade to: a release before 0.9.13

1. Check installed version

apt-cache policy musl || rpm -q musl || musl --version

2. UPGRADE to 1.2.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade musl

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade musl

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.9.13 (Debian / Ubuntu)

apt-cache madison musl sudo apt install musl=<VERSION_BEFORE_0.9.13> sudo apt-mark hold musl

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list musl sudo dnf downgrade musl-<VERSION_BEFORE_0.9.13> sudo dnf versionlock add musl

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-26519?

musl: upgrade to 1.2.6. Exact commands for each OS are on this page.

Is CVE-2025-26519 being exploited?

CVE-2025-26519 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-26519 affect?

CVE-2025-26519 affects musl. Severity is high (CVSS 8.1). musl libc 0.9.13 through 1.2.5 before 1.2.6 has an out-of-bounds write vulnerability when an attacker can trigger iconv conversion of untrusted EUC-KR text to UTF-8.

How urgent is CVE-2025-26519?

Priority 35/100. High severity

References

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