7.5

CVE-2026-9546: curl

CVSS: 7.5v3.1HighModified
AliasesALPINE-CVE-2026-9546UBUNTU-CVE-2026-9546DEBIAN-CVE-2026-9546
Published 03-07-2026Last modified 15-09-2026
Open JSON

Vulnerability summary

CVE-2026-9546 is a high (CVSS 7.5) vulnerability in curl. EPSS estimates a 0.65% chance of exploitation in the next 30 days, higher than 50.5% 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
0.65%
0%100%
Low · +0.16 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 3 · Related 2
OPENSUSE-SU-2026:11230-1RHSA-2026:29017RHSA-2026:34975CGA-26P3-5M82-859C

Timeline

  1. 03-07-2026
    PublishedVulnerability first disclosed.
  2. 15-09-2026
    Last modifiedVulnerability information updated.

Description

A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared. While the documentation states that passing NULL to `CURLOPT_REFERER` suppresses the header, the option failed to clear the internal state. As a result, the previous referrer string was erroneously reused and sent in subsequent requests, potentially leaking sensitive information to unintended servers.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.65%

Chance of exploitation in the next 30 days

Percentile

51%

Versus all other CVEs

30-day change

+0.16 pp

From 0.49% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.65%

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

Chainguard10 products
  • eco-python-curl< 8.21.0-r0
  • eco-python-curl-minimal< 8.21.0-r0
  • eco-python-curl-minimal-bin< 8.21.0-r0
  • eco-python-curl-minimal-dev< 8.21.0-r0
  • eco-python-curl-minimal-doc< 8.21.0-r0
Alpine1 product
  • curl≥ 8.18.0, < 8.22.0-r0 | ≥ 8.18.0, < 8.21.0-r0
Curl1 product
  • curl≥ 8.18.0, < 8.20.1 | ≥ 2cb868242dc2ac9cd52ee64987ef51d5964a56f9, < 862e8a74a84478d82973471b4f49dc2746c1780e | 8.20.0 | 8.19.0 | 8.18.0
Debian1 product
  • curl< 8.21.0~rc2-1
Haxx1 product
  • curl≥ 8.18.0, < 8.21.0
Ubuntu1 product
  • curlAll versions (No fix recorded)

6 vendors · 15 products

References

10 links