CVE-2013-7459: Heap-based buffer overflow in the ALGnew function in block_templace.c in Python Cryptography Toolkit (aka pycr

Q: How do I fix CVE-2013-7459?

pycrypto: upgrade to newer than 2.6.1; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2013-7459 being exploited?

CVE-2013-7459 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-2013-7459 affect?

CVE-2013-7459 affects pycrypto, fedora. Severity is critical (CVSS 9.8). Heap-based buffer overflow in the ALGnew function in block_templace.c in Python Cryptography Toolkit (aka pycrypto) allows remote attackers to execute arbitrary code as demonstrated by a crafted iv parameter to cryptmsg.py.

Q: How urgent is CVE-2013-7459?

Priority 68/100. Critical severity; EPSS top 5%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADEMITIGATE

CVE-2013-7459 is a critical-severity flaw (CVSS 9.8) affecting pycrypto, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap-based buffer overflow in the ALGnew function in block_templace.c in Python Cryptography Toolkit (aka pycrypto) allows remote attackers to execute arbitrary code as demonstrated by a crafted iv parameter to cryptmsg.py.

Why this priority

Critical severity
EPSS top 5%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	9.6% (top 5%)
CISA exploited list	No
Weakness	CWE-119
Published	2017-02-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: dlitz · fedoraproject

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

Am I affected?

Timeline

2017-02-15 15:59 UTCPublished CVE record published
2026-06-17 00:02 UTCUpdated Record last modified

dlitz pycrypto UPGRADE

Affected: <= 2.6.1

Fixed in: newer than 2.6.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 2.6.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pycrypto

Note

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

fedoraproject fedora MITIGATE

Affected: 24 · 25

Fixed in: no fixed release known

Safe to downgrade to: a release before 24

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.

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-2013-7459?

pycrypto: upgrade to newer than 2.6.1; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2013-7459 being exploited?

CVE-2013-7459 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-2013-7459 affect?

CVE-2013-7459 affects pycrypto, fedora. Severity is critical (CVSS 9.8). Heap-based buffer overflow in the ALGnew function in block_templace.c in Python Cryptography Toolkit (aka pycrypto) allows remote attackers to execute arbitrary code as demonstrated by a crafted iv parameter to cryptmsg.py.

How urgent is CVE-2013-7459?

Priority 68/100. Critical severity; EPSS top 5%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities

Related CVEs

CVE-2018-6594 HIGH 7.5 UPGRADE MITIGATE lib/Crypto/PublicKey/ElGamal.py in PyCrypto through 2.6.1 generates weak ElGamal key parameters, which allows

References

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