CVE-2009-0544: Buffer overflow in the PyCrypto ARC2 module 2.0.1 allows remote attackers to cause a denial of service and pos

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HIGH 10.0DOWNGRADE

CVE-2009-0544 is a high-severity flaw (CVSS 10.0) affecting arc2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in the PyCrypto ARC2 module 2.0.1 allows remote attackers to cause a denial of service and possibly execute arbitrary code via a large ARC2 key length.

Why this priority

Critical severity
EPSS top 4%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	11.5% (top 4%)
CISA exploited list	No
Weakness	CWE-119
Published	2009-02-12
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: pycrypto

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

Am I affected?

Timeline

2009-02-12 17:30 UTCPublished CVE record published
2026-06-16 23:05 UTCUpdated Record last modified

pycrypto arc2 DOWNGRADE

Affected: 2.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0.1

1. Check installed version

apt-cache policy arc2 || rpm -q arc2 || arc2 --version

2. No fixed release: DOWNGRADE to a release before 2.0.1 (Debian / Ubuntu)

apt-cache madison arc2 sudo apt install arc2=<VERSION_BEFORE_2.0.1> sudo apt-mark hold arc2

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

dnf --showduplicates list arc2 sudo dnf downgrade arc2-<VERSION_BEFORE_2.0.1> sudo dnf versionlock add arc2

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: PyCrypto ARC2 Module - Remote Buffer Overflow

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-2009-0544?

arc2: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-0544 being exploited?

CVE-2009-0544 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-2009-0544 affect?

CVE-2009-0544 affects arc2. Severity is high (CVSS 10.0). Buffer overflow in the PyCrypto ARC2 module 2.0.1 allows remote attackers to cause a denial of service and possibly execute arbitrary code via a large ARC2 key length.

How urgent is CVE-2009-0544?

Priority 64/100. Critical severity; EPSS top 4%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2012-5873 MEDIUM 5.3 UPGRADE ARC (aka ARC2) through 2011-12-01 allows reflected XSS via the end_point.php query parameter in an output=html
CVE-2012-5872 CRITICAL 9.8 UPGRADE ARC (aka ARC2) through 2011-12-01 allows blind SQL Injection in getTriplePatternSQL in ARC2_StoreSelectQueryHa

References

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