CVE-2026-80255: secure cookie attribute bypass with tab
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the `Secure` attribute causes curl to store the cookie without its Secure flag. The cookie might then wrongfully be sent over plaintext HTTP on subsequent requests to the same host.
Description quoted from the CVE record (assigned by curl, published 2026-09-06).
Weakness: Information Exposure Through Sent Data; CWE-201 Insertion of Sensitive Information Into Sent Data
How it can be exploited
Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: yes. Technical impact: partial.
Public exploit evidence (Exploit Observer)
Also known as: EUVD-2026-72151, GHSA-vmmm-3jqx-jgx8
VEDAS cluster: VEDAS:FRETLESSFROG
Exploit Observer has no public exploit code that names this CVE or one of its aliases.
Research and write-ups (2)
- Research or write-up: https://curl.se/docs/CVE-2026-80255.html
- Research or write-up: https://curl.se/docs/CVE-2026-80255.json
Vulnerability databases and vendor advisories (12)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://access.redhat.com/security/cve/cve-2026-80255
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2026-72151
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-vmmm-3jqx-jgx8
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-80255
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/CURL-CVE-2026-80255
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/ROOT-OS-ALPINE-320-CVE-2026-80255
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/ROOT-OS-ALPINE-321-CVE-2026-80255
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/ROOT-OS-ALPINE-322-CVE-2026-80255
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/ROOT-OS-DEBIAN-13-CVE-2026-80255
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/UBUNTU-CVE-2026-80255
- Vulnerability database or vendor advisory: https://ubuntu.com/security/CVE-2026-80255
- Vulnerability database or vendor advisory: https://www.suse.com/security/cve/CVE-2026-80255
7 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.005
low predicted chance of attack - VEDAS
- 0.987
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- None yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| curl curl | from 8.13.0 before 8.14.2 from 8.15.0 before 8.16.1 from 8.17.0 before 8.20.1 from 8.21.0 before 8.22.0 | Not stated |
| curl curl | from 1aea05a6c269 before 4f6aa41a0145 (git commit) | Not stated |
| curl curl | version 8.21.0 version 8.20.0 version 8.19.0 version 8.18.0 version 8.17.0 version 8.16.0 version 8.15.0 version 8.14.1 and 2 more ranges | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
Exploit Observer also maps it to: haxx curl.
How to fix it
Fixed versions stated in the CVE record: 8.14.2, 8.16.1, 8.20.1, 8.22.0.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Other references
- https://curl.se/docs/CVE-2026-80255.json
- https://curl.se/docs/CVE-2026-80255.html
- https://hackerone.com/reports/3972395
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.