CVE-2023-1521: On Linux the sccache client can execute arbitrary code with the privileges of a local sccache server, by prelo

Q: How do I fix CVE-2023-1521?

sccache: upgrade to 0.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2023-1521 being exploited?

CVE-2023-1521 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-1521 affect?

CVE-2023-1521 affects sccache. Severity is high (CVSS 7.8). On Linux the sccache client can execute arbitrary code with the privileges of a local sccache server, by preloading the code in a shared library passed to LD_PRELOAD. If the server is run as root (which is the default when installing the

Q: How urgent is CVE-2023-1521?

Priority 45/100. High severity; Public exploit reference; On your watchlist

This month

HIGH 7.8WATCHLISTUPGRADE

CVE-2023-1521 is a high-severity flaw (CVSS 7.8) affecting sccache. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

On Linux the sccache client can execute arbitrary code with the privileges of a local sccache server, by preloading the code in a shared library passed to LD_PRELOAD. If the server is run as root (which is the default when installing the snap package https://snapcraft.io/sccache ), this means a user running the sccache client can get root privileges.

Why this priority

High severity
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 70%)
CISA exploited list	No
Weakness	CWE-426
Published	2024-11-26
Last modified	2026-06-17

Publisher (CNA): Mozilla Corporation · Vendor: mozilla

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

Am I affected?

Timeline

2024-11-26 12:15 UTCPublished CVE record published
2026-06-17 05:28 UTCUpdated Record last modified

mozilla sccache UPGRADE

Affected: < 0.4.0

Fixed in: 0.4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 0.4.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sccache

Note

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

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-2023-1521?

sccache: upgrade to 0.4.0. Exact commands for each OS are on this page.

Is CVE-2023-1521 being exploited?

CVE-2023-1521 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-2023-1521 affect?

CVE-2023-1521 affects sccache. Severity is high (CVSS 7.8). On Linux the sccache client can execute arbitrary code with the privileges of a local sccache server, by preloading the code in a shared library passed to LD_PRELOAD. If the server is run as root (which is the default when installing the

How urgent is CVE-2023-1521?

Priority 45/100. High severity; Public exploit reference; On your watchlist

References

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