7.5

CVE-2026-6276: curl Origin Validation Error

CVSS: 7.5v3.1HighModified
AliasesALPINE-CVE-2026-6276UBUNTU-CVE-2026-6276DEBIAN-CVE-2026-6276
Published 13-05-2026Last modified 15-09-2026
Open JSON

Vulnerability summary

CVE-2026-6276 is a high (CVSS 7.5) Origin Validation Error vulnerability in curl. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 27.2% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
40/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.35%
0%100%
Low · +0.05 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 7 · Related 7
OPENSUSE-SU-2026:10674-1OPENSUSE-SU-2026:20973-1RHSA-2026:12916SUSE-SU-2026:22146-1SUSE-SU-2026:22156-1SUSE-SU-2026:2703-1

Timeline

  1. 13-05-2026
    PublishedVulnerability first disclosed.
  2. 15-09-2026
    Last modifiedVulnerability information updated.

Description

Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.35%

Chance of exploitation in the next 30 days

Percentile

27%

Versus all other CVEs

30-day change

+0.05 pp

From 0.29% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.35%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (hackerone.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Alpine1 product
  • curl≥ 7.71.0, < 8.14.1-r3 | ≥ 7.71.0, < 8.14.1-r4 | ≥ 7.71.0, < 8.20.0-r0
Chainguard1 product
  • libcurl4All versions (No fix recorded)
Curl1 product
  • curl≥ 7.71.0, < 8.14.2 | ≥ 8.15.0, < 8.16.1 | ≥ 8.17.0, < 8.20.0 | ≥ e15e51384a423be31318b3c9c7d612a1aae661fd, < 3a19987a87f393d9394fe5acc7643f6c263c92db | 8.19.0 | 8.18.0 | 8.17.0 | 8.16.0 | 8.15.0 | 8.14.1 | 8.14.0 | 8.13.0 | 8.12.1 | 8.12.0 | 8.11.1 | 8.11.0 | 8.10.1 | 8.10.0 | 8.9.1 | 8.9.0 | 8.8.0 | 8.7.1 | 8.7.0 | 8.6.0 | 8.5.0 | 8.4.0 | 8.3.0 | 8.2.1 | 8.2.0 | 8.1.2 | 8.1.1 | 8.1.0 | 8.0.1 | 8.0.0 | 7.88.1 | 7.88.0 | 7.87.0 | 7.86.0 | 7.85.0 | 7.84.0 | 7.83.1 | 7.83.0 | 7.82.0 | 7.81.0 | 7.80.0 | 7.79.1 | 7.79.0 | 7.78.0 | 7.77.0 | 7.76.1 | 7.76.0 | 7.75.0 | 7.74.0 | 7.73.0 | 7.72.0 | 7.71.1 | 7.71.0
Debian1 product
  • curlAll versions (No fix recorded) | < 8.14.1-2+deb13u4 | < 8.20.0~rc3-1
Haxx1 product
  • curl≥ 7.71.0, < 8.20.0
Ubuntu1 product
  • curl< 7.81.0-1ubuntu1.24 | < 8.5.0-2ubuntu10.9 | < 8.14.1-2ubuntu1.3 | < 8.18.0-1ubuntu2.1
Wolfi1 product
  • libcurl4All versions (No fix recorded)

7 vendors · 7 products

References

10 links