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Fencer Vulns
high 7.5

CVE-2026-80255 json

secure cookie attribute bypass with tab

published 2026-09-06 2 mo ago modified 2026-09-15 55 d ago also EUVD-2026-72151

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • curl curl 8.14.2, 8.16.1, 8.20.1, 8.22.0
  • curl Debian 14 8.22.0-1

debian advisories DEBIAN-CVE-2026-80255

  • curl Ubuntu 26.10 8.20.0-2ubuntu11
  • curl Ubuntu 26.04 LTS 8.18.0-1ubuntu2.7

ubuntu advisories UBUNTU-CVE-2026-80255

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl hummingbird 1 8.22.0-0.1.hum1
  • libcurl hummingbird 1 8.22.0-0.1.hum1
  • libcurl-minimal hummingbird 1 8.22.0-0.1.hum1

red hat advisories RHSA-2026:63161

  • curl SLE Module for Basesystem 15 SP7 8.22.0-150700.7.33.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.98.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.22.0-150600.4.58.1

suse advisories SUSE-SU-2026:5069-1SUSE-SU-2026:5068-1SUSE-SU-2026:4954-1

  • curl openSUSE Tumbleweed 8.22.0-1.1

opensuse advisories openSUSE-SU-2026:11696-1

  • curl Alpine 3.24, Alpine 3.23 8.22.0-r0

alpine advisories ALPINE-CVE-2026-80255

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-80255 updated cvss 3.7

curl: curl: Information disclosure due to secure cookie attribute bypass

  • Red Hat Satellite 6 openvox-agent
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images curl 8.22.0-0.1.hum1, libcurl 8.22.0-0.1.hum1, libcurl-minimal 8.22.0-0.1.hum1
    fixed: vendor fix RHSA-2026:63161
  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9 Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal Red Hat Enterprise Linux 9 curl, rust, cargo, clippy, libcurl, rustfmt, +13 more Red Hat Enterprise Linux 10 curl, igvm, rust, snphost, trustee, s390utils
    +6 more products
    Red Hat Enterprise Linux AI (RHEL AI) 3 rust Red Hat JBoss Core Services jbcs-httpd24-curl, jbcs-httpd24-libcurl Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9 Red Hat Satellite 6 foreman, foreman-cli, foreman-ec2, foreman-gce, puppet-agent, foreman-ovirt, +10 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3972395 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

  • curl curl

Classification

Weakness
  • CWE-201 Insertion of Sensitive Information Into Sent Data

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.