CVE-2026-8924: A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Pu

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CRITICAL 9.1REMOTEUPGRADE

CVE-2026-8924 is a critical-severity flaw (CVSS 9.1) affecting curl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check. This enables an attacker-controlled origin to inject cookies that curl subsequently scopes and transmits to unrelated third-party domains.

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

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	0.7% (top 49%)
CISA exploited list	No
Weakness	CWE-201
Published	2026-07-03
Last modified	2026-09-15

Publisher (CNA): curl · Vendor: haxx

Last updated 2026-09-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-03 07:16 UTCPublished CVE record published
2026-09-15 07:16 UTCUpdated Record last modified

haxx curl UPGRADE

Affected: >= 7.46.0 and < 8.21.0

Fixed in: 8.21.0

Safe to downgrade to: a release before 7.46.0

1. Check installed version

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

2. UPGRADE to 8.21.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade curl

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 7.46.0 (Debian / Ubuntu)

apt-cache madison curl sudo apt install curl=<VERSION_BEFORE_7.46.0> sudo apt-mark hold curl

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

dnf --showduplicates list curl sudo dnf downgrade curl-<VERSION_BEFORE_7.46.0> sudo dnf versionlock add curl

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 46 · python3.11 · FIXED · 3.11.18-1.fc46 · FEDORA-2026-cc775894f4 · source

sudo dnf upgrade --advisory=FEDORA-2026-cc775894f4

Ubuntu 20.04 · curl · FIXED · 7.68.0-1ubuntu2.25+esm4

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "7.68.0-1ubuntu2.25+esm4" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · curl · FIXED · 7.81.0-1ubuntu1.25

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "7.81.0-1ubuntu1.25" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · curl · FIXED · 8.5.0-2ubuntu10.10

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "8.5.0-2ubuntu10.10" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 25.10 · curl · FIXED · 8.14.1-2ubuntu1.4

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "8.14.1-2ubuntu1.4" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · curl · NO FIX YET

Debian 13 · curl · FIXED · 8.14.1-2+deb13u7

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "8.14.1-2+deb13u7" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · curl · FIXED · curl-8.12.1-4.el10_2.6

sudo dnf upgrade --advisory=RHSA-2026:69125 rpm -q curl

RHEL 10.0 Extended Update Support · curl · FIXED · curl-8.12.1-1.el10_0.10

sudo dnf upgrade --advisory=RHSA-2026:72506 rpm -q curl

RHEL 9 · curl · FIXED · curl-7.76.1-40.el9_8.8

sudo dnf upgrade --advisory=RHSA-2026:80511 rpm -q curl

RHEL 10 · igvm · NOT AFFECTED

RHEL 10 · rust · NOT AFFECTED

Alpine 3.21 · curl · FIXED · curl-8.14.1-r3

apk add --upgrade curl apk info -v curl

Alpine 3.22 · curl · FIXED · curl-8.14.1-r4

apk add --upgrade curl apk info -v curl

Alpine 3.23 · curl · FIXED · curl-8.22.0-r0

apk add --upgrade curl apk info -v curl

Alpine 3.24 · curl · FIXED · curl-8.21.0-r0

apk add --upgrade curl apk info -v curl

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2132 · source

sudo dnf update --advisory=ALAS2023-2026-2132

Amazon Linux 2 · see advisory · FIXED · ALAS2-2026-3953 · source

sudo yum update --advisory=ALAS2-2026-3953

Advisories and coverage

Official advisories

Amazon Linux 2 ALAS: ALAS2-2026-3953 (important): curl 2026-09-28

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-2026-8924?

curl: upgrade to 8.21.0. Exact commands for each OS are on this page.

Is CVE-2026-8924 being exploited?

CVE-2026-8924 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-2026-8924 affect?

CVE-2026-8924 affects curl. Severity is critical (CVSS 9.1). A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check. This enables an attacker-controlled origin to inject cookies that curl subsequently scopes and transmits t

How urgent is CVE-2026-8924?

Priority 58/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

curl vulnerabilities

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References

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