CVE-2024-8158: A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user with

Q: How do I fix CVE-2024-8158?

lib9p: upgrade to 2024-08-24. Exact commands for each OS are on this page.

Q: Is CVE-2024-8158 being exploited?

CVE-2024-8158 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-2024-8158 affect?

CVE-2024-8158 affects lib9p. Severity is medium (CVSS 6.5). A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user within the configured auth server to impersonate any other valid filesystem user. This is due to lib9p not properly verifying that th

Q: How urgent is CVE-2024-8158?

Priority 31/100. No elevated risk signals yet.

Routine

MEDIUM 6.5UPGRADE

CVE-2024-8158 is a medium-severity flaw (CVSS 6.5) affecting lib9p. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user within the configured auth server to impersonate any other valid filesystem user. This is due to lib9p not properly verifying that the uname given in the Tauth and Tattach 9p messages matches the client UID returned from the factotum authentication handshake. The only filesystem making use of these functions within the base 9front systems

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-639
Published	2024-08-25
Last modified	2026-06-17

Publisher (CNA): 9front · Vendor: 9front

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

Am I affected?

Timeline

2024-08-25 22:15 UTCPublished CVE record published
2026-06-17 08:22 UTCUpdated Record last modified

9front lib9p UPGRADE

Affected: < 2024-08-24

Fixed in: 2024-08-24

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy lib9p || rpm -q lib9p || lib9p --version

2. UPGRADE to 2024-08-24 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade lib9p

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade lib9p

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-2024-8158?

lib9p: upgrade to 2024-08-24. Exact commands for each OS are on this page.

Is CVE-2024-8158 being exploited?

CVE-2024-8158 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-2024-8158 affect?

CVE-2024-8158 affects lib9p. Severity is medium (CVSS 6.5). A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user within the configured auth server to impersonate any other valid filesystem user. This is due to lib9p not properly verifying that th

How urgent is CVE-2024-8158?

Priority 31/100. No elevated risk signals yet.

References

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