CVE-2026-8924
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Description
A flaw was found in curl's cookie parsing logic. A malicious HTTP server can exploit this by setting 'super cookies' that bypass the Public Suffix List check. This allows an attacker-controlled origin to inject cookies that curl then transmits to unrelated third-party domains, leading to compromising request integrity.
Statement
Moderate: Red Hat rates this flaw Moderate (CVSS 6.5) compared to CISA's Critical (9.1). The scoring difference is due to two factors: first, exploitation requires the victim's curl to connect using a trailing-dot hostname (e.g., Content from example.co.uk is not included.https://example.co.uk.), a format that is uncommon in practice and incompatible with TLS SNI; second, the direct impact is cookie injection into outbound requests — not exfiltration of victim data to the attacker. The curl project itself rates this flaw Low severity. Red Hat products that use curl for HTTP communication are affected, but the trailing-dot precondition significantly limits real-world exploitability. This flaw has not been shown to enable impacts beyond session integrity modification.
Mitigation
Do 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
Additional information
- This content is not included.Bugzilla 2496765: curl: curl: Cookie injection via malicious HTTP server using super cookies
- Content from cwe.mitre.org is not included.CWE-565: Reliance on Cookies without Validation and Integrity Checking
External References
Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2026-8924
Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2026-8924
Content from curl.se is not included.https://curl.se/docs/CVE-2026-8924.html
Content from curl.se is not included.https://curl.se/docs/CVE-2026-8924.json
Content from hackerone.com is not included.https://hackerone.com/reports/3733905
Affected Packages and Issued Red Hat Security Errata
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.
| Products / Services | Components | State | Errata |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | curl | Fix deferred | |
| Red Hat Enterprise Linux 6 | curl | Fix deferred | |
| Red Hat Enterprise Linux 7 | curl | Fix deferred | |
| Red Hat Enterprise Linux 8 | curl | Fix deferred | |
| Red Hat Enterprise Linux 9 | curl | Fix deferred | |
| Red Hat Hardened Images | curl-main | Fixed | RHSA-2026:29017 |
| Red Hat Hardened Images | rust-main | Fixed | RHSA-2026:34975 |
| Red Hat OpenShift Container Platform 4 | rhcos | Fix deferred | |
| Red Hat OpenShift Dev Spaces | devspaces/code-rhel9 | Fix deferred | |
| Red Hat Trusted Profile Analyzer | rhtpa/rhtpa-trustification-service-rhel9 | Fix deferred |
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| CVSS v3 Base Score | 6.5 | N/A | 9.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality Impact | None | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
CVSS v3 Vector
Red Hat CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
cve.org CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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