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Public proof of conceptFix available

CVE-2026-8924

A public proof of concept exists; no exploitation attested.

  • Published2026-07-03
  • Fixed in8.21.0
  • WeaknessCWE-201

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-07-0307:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-8924?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-8924?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Haxx curl
BranchAffectedFixed in
8.21≥ 7.46.0, < 8.21.08.21.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libcurlAlmaLinux:10all versions · fixed in 8.12.1-4.el10_2.6and 3 other packages
  • libcurlAlmaLinux:9all versions · fixed in 7.76.1-40.el9_8.8and 4 other packages

Vendor advisories

  • CVE-2026-8924 Red Hat Product Security227 products fixed · 23 known affected

    curl: curl: Cookie injection via malicious HTTP server using super cookies

    curl as a component of Red Hat Enterprise Linux 6 · curl.src as a component of Red Hat Enterprise Linux 6 · libcurl as a component of Red Hat Enterprise Linux 6 · +20 more

  • RHSA-2026:82939 Red Hat Product Security5 products fixed

    Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 security update

  • RHSA-2026:80511 Red Hat Product Security74 products fixed

    Red Hat Security Advisory: curl security update

  • RHSA-2026:79357 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Cost Management On-Premise container image update

  • RHSA-2026:72506 Red Hat Product Security49 products fixed

    Red Hat Security Advisory: curl security update

  • RHSA-2026:69125 Red Hat Product Security49 products fixed

    Red Hat Security Advisory: curl security update

3 more advisories

Full record on NVD

Fix

  1. Update Haxx curl to 8.21.0
  2. Vendor fix Red Hat Product Security RHSA-2026:82939 · 5 productsThe container images provided by this release, apart from the installer, should be deployed using rhui-installer utility. See the official documentation for more details.
  3. Vendor fix Red Hat Product Security RHSA-2026:80511 · 74 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2026:79357 · 1 productThe container image provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io using the "podman pull" command.
  5. Vendor fix Red Hat Product Security RHSA-2026:56869 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  6. Vendor fix Red Hat Product Security CVE-2026-8924 · 39 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
  7. Workaround from the vendor Red Hat Product Security RHSA-2026:82939 · 5 productsDo not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionpoc2026-07-06
  • OpenCVESSVC decisionpoc—
  • CISA-ADPCVSS 3.19.12026-07-06
  • CNAweakness (CWE)CWE-201read 2026-10-23
  • FIRST EPSSEPSS score0.7 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
2026-07-03
Last Modified
2026-09-15
NVD status
Modified

Frequently asked questions

What is CVE-2026-8924?

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.

Is CVE-2026-8924 actively exploited?

A proof-of-concept exploit exists for CVE-2026-8924, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-8924?

CVE-2026-8924 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

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