CVE-2025-9086 — Out of bounds read for cookie path
1. A cookie is set using the `secure` keyword for `https://target` 2. curl is redirected to or otherwise made to speak with `http://target` (same hostname, but using clear text HTTP) using the same cookie set 3. The same cookie name is set - but with only a slash as path (`path="/"`). Since this site is not secure, the cookie *should* be ignored. 4. A bug in the path comparison logic makes curl read outside a heap buffer boundary The bug either causes a crash or it potentially makes the comparison come to the wrong conclusion and lets the clear-text site override the contents of the secure cookie, contrary to expectations and depending on the memory contents immediately following the single-byte allocation that holds the path. The presumed and correct behavior would be to plainly ignore the second set of the cookie since it was already set as secure on a secure host so overriding it on an insecure host should not be okay.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 1.4% (30-day exploitation probability)+11
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — curl.se (NIST National Vulnerability Database)
- Documented patch — www.openwall.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Curl Curl, Debian Debian Linux, Haxx Curl).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Curl | Curl | ≥ 8.13.0 and < 8.14.2≥ 8.15.0 and < 8.16.0≥ 1aea05a6c2699e80c75936d58569851555acd603 and < c6ae07c6a541e0e96d0040afb62b45dd37711300version 8.15.0version 8.14.1version 8.14.0version 8.13.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Debian | Debian Linux | version 11.0 | Vulnerable | NIST National Vulnerability Database |
| Haxx | Curl | ≥ 8.13.0 and < 8.16.0 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.5 | CVSS 3.1 | High | 3.9 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 7.5 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.5 | CVSS 3.1 | High | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · curl/curl
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · haxx/curl, debian/debian linux
- CVSS changed · 7.5
- Source status changed · → Modified
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 19, 2026 – Oct 19, 2026
- 1× Official description updated · Oct 19, 2026 – Oct 19, 2026
References
9 on the record
- curl.se/docs/CVE-2025-9086.json
- www.openwall.com/lists/oss-security/2025/09/10/1
- curl.se/docs/CVE-2025-9086.html
- hackerone.com/reports/3294999
- cert-portal.siemens.com/productcert/html/ssa-089022.html
- github.com/advisories/GHSA-v676-f8gm-92r9
- lists.debian.org/debian-lts-announce/2026/01/msg00002.html
- nvd.nist.gov/vuln/detail/CVE-2025-9086
- cert-portal.siemens.com/productcert/html/ssa-253495.html
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-92392 HTTP/2 upload Use-After-Free 5d
- High CVE-2026-80229 OpenSSL provider use-after-free Sep 6, 2026
- High CVE-2026-82209 domain-scoped PSL domain cookie Sep 6, 2026
- High CVE-2026-80230 OpenSSL pinning bypass Sep 6, 2026
- High CVE-2026-80231 native CA store conn reuse Sep 6, 2026
- High CVE-2026-80255 secure cookie attribute bypass with tab Sep 6, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2025-9086 is "Out of bounds read for cookie path", rated High. It affects Curl (Curl); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 1.40% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.