CVE-2025-40931: Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id. Apache::Session::Ge

Q: How do I fix CVE-2025-40931?

apache\: upgrade to newer than 1.94. Exact commands for each OS are on this page.

Q: Is CVE-2025-40931 being exploited?

CVE-2025-40931 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-2025-40931 affect?

CVE-2025-40931 affects apache\. Severity is critical (CVSS 9.1). Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id. Apache::Session::Generate::MD5 generates session ids insecurely. The default session id generator returns a MD5 hash seeded with the built-in rand()

Q: How urgent is CVE-2025-40931?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

This month

CRITICAL 9.1REMOTEWATCHLISTUPGRADE

CVE-2025-40931 is a critical-severity flaw (CVSS 9.1) affecting apache\. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id. Apache::Session::Generate::MD5 generates session ids insecurely. The default session id generator returns a MD5 hash seeded with the built-in rand() function, the epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable f

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 51%)
CISA exploited list	No
Weakness	CWE-338, CWE-340
Published	2026-03-05
Last modified	2026-06-17

Publisher (CNA): CPANSec · Vendor: chorny

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

Am I affected?

Timeline

2026-03-05 02:16 UTCPublished CVE record published
2026-06-17 09:22 UTCUpdated Record last modified

chorny apache\ UPGRADE

Affected: <= 1.94

Fixed in: newer than 1.94

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.94 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade apache

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-2025-40931?

apache\: upgrade to newer than 1.94. Exact commands for each OS are on this page.

Is CVE-2025-40931 being exploited?

CVE-2025-40931 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-2025-40931 affect?

CVE-2025-40931 affects apache\. Severity is critical (CVSS 9.1). Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id. Apache::Session::Generate::MD5 generates session ids insecurely. The default session id generator returns a MD5 hash seeded with the built-in rand()

How urgent is CVE-2025-40931?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

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References

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