CVE-2009-1251: Heap-based buffer overflow in the cache manager in the client in OpenAFS 1.0 through 1.4.8 and 1.5.0 through 1

This month

HIGH 10.0MITIGATEDOWNGRADE

CVE-2009-1251 is a high-severity flaw (CVSS 10.0) affecting unix, openafs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap-based buffer overflow in the cache manager in the client in OpenAFS 1.0 through 1.4.8 and 1.5.0 through 1.5.58 on Unix platforms allows remote attackers to cause a denial of service (system crash) or possibly execute arbitrary code via an RX response containing more data than specified in a request, related to use of XDR arrays.

Why this priority

Critical severity
EPSS top 6%: very likely to be exploited

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	6.4% (top 6%)
CISA exploited list	No
Weakness	CWE-119
Published	2009-04-09
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: openafs · unix

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2009-04-09 00:30 UTCPublished CVE record published
2026-06-16 23:06 UTCUpdated Record last modified

unix unix MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

openafs openafs DOWNGRADE

Affected: 1.0 · 1.0.1 · 1.0.2 · 1.0.3 · 1.0.4 · 1.0.4a · 1.1 · 1.1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison openafs sudo apt install openafs=<VERSION_BEFORE_1.0> sudo apt-mark hold openafs

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openafs sudo dnf downgrade openafs-<VERSION_BEFORE_1.0> sudo dnf versionlock add openafs

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-2009-1251?

unix: mitigate or apply the listed mitigation; openafs: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-1251 being exploited?

CVE-2009-1251 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-2009-1251 affect?

CVE-2009-1251 affects unix, openafs. Severity is high (CVSS 10.0). Heap-based buffer overflow in the cache manager in the client in OpenAFS 1.0 through 1.4.8 and 1.5.0 through 1.5.58 on Unix platforms allows remote attackers to cause a denial of service (system crash) or possibly execute arbitrary code via

How urgent is CVE-2009-1251?

Priority 58/100. Critical severity; EPSS top 6%: very likely to be exploited

Related CVEs

CVE-2025-71263 HIGH 7.4 MITIGATE In UNIX Fourth Research Edition (v4), the su command is vulnerable to a buffer overflow due to the 'password'

References

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