CVE-2026-57941: Use After Free vulnerability in Apache HTTP Server's mod_http2 via shared session->bbtmp re-entrancy This i

This month

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-57941 is a critical-severity flaw (CVSS 9.8) affecting http server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Use After Free vulnerability in Apache HTTP Server's mod_http2 via shared session->bbtmp re-entrancy This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

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	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-10-01
Last modified	2026-10-05

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-05 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-01 17:17 UTCPublished CVE record published
2026-10-05 13:29 UTCUpdated Record last modified

apache http server UPGRADE

Affected: >= 2.4.0 and < 2.4.69

Fixed in: 2.4.69

Safe to downgrade to: a release before 2.4.0

1. Check installed version

apt-cache policy http-server || rpm -q http-server || http-server --version

2. UPGRADE to 2.4.69 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade http-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade http-server

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2.4.0 (Debian / Ubuntu)

apt-cache madison http-server sudo apt install http-server=<VERSION_BEFORE_2.4.0> sudo apt-mark hold http-server

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list http-server sudo dnf downgrade http-server-<VERSION_BEFORE_2.4.0> sudo dnf versionlock add http-server

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.

Exact fixes by distribution

Fedora ELN · edk2 · FIXED · 20260812-12.eln159 · FEDORA-2026-e316b6370a · source

sudo dnf upgrade --advisory=FEDORA-2026-e316b6370a

Fedora 46 · perl-Mojo-DOM58 · FIXED · 3.003-1.fc46 · FEDORA-2026-d5412af3de · source

sudo dnf upgrade --advisory=FEDORA-2026-d5412af3de

Debian 12 · apache2 · NO FIX YET

Debian 13 · apache2 · FIXED · 2.4.69-1~deb13u1

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.69-1~deb13u1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · httpd · NOT AFFECTED

RHEL 10 · mod_http2 · NO FIX YET

RHEL 6 · httpd · NOT AFFECTED

RHEL 7 · httpd · NOT AFFECTED

RHEL 8 · httpd:2.4/httpd · NOT AFFECTED

Alpine 3.21 · apache2 · FIXED · apache2-2.4.69-r0

apk add --upgrade apache2 apk info -v apache2

Alpine 3.22 · apache2 · FIXED · apache2-2.4.69-r0

apk add --upgrade apache2 apk info -v apache2

Alpine 3.23 · apache2 · FIXED · apache2-2.4.69-r0

apk add --upgrade apache2 apk info -v apache2

Alpine 3.24 · apache2 · FIXED · apache2-2.4.69-r0

apk add --upgrade apache2 apk info -v apache2

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-3202 · source

sudo dnf update --advisory=ALAS2023-2026-3202

Amazon Linux 2 · see advisory · FIXED · ALAS2-2026-3990 · source

sudo yum update --advisory=ALAS2-2026-3990

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-2026-57941?

http server: upgrade to 2.4.69. Exact commands for each OS are on this page.

Is CVE-2026-57941 being exploited?

CVE-2026-57941 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-2026-57941 affect?

CVE-2026-57941 affects http server. Severity is critical (CVSS 9.8). Use After Free vulnerability in Apache HTTP Server's mod_http2 via shared session->bbtmp re-entrancy This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

How urgent is CVE-2026-57941?

Priority 59/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Apache HTTP Server vulnerabilities

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References

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