9.1

CVE-2026-8927: env-set cross-proxy Digest auth state leak

Modified
AliasesALPINE-CVE-2026-8927RHSA-2026:55432UBUNTU-CVE-2026-8927
Published 03-07-2026Last modified 15-09-2026

Vulnerability summary

CVE-2026-8927 is a critical (CVSS 9.1) Authentication Bypass by Capture-replay vulnerability in curl. EPSS estimates a 0.50% chance of exploitation in the next 30 days, higher than 42.9% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Prioritisepublic exploit

Public exploit (reference, Date unknown)

Source freshness unavailable

How is this decided?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.50%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 14 · Related 12
OPENSUSE-SU-2026:11230-1OPENSUSE-SU-2026:21272-1RHSA-2026:29017RHSA-2026:34975RHSA-2026:69126RHSA-2026:72506

Timeline

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

Description

When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.

CVSS metrics

8 scores · 8 sources · 1 version

EPSS trend

Probability

0.50%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.50% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (hackerone.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard11 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
Redhat8 products
  • curl< 0:8.12.1-4.el10_2.4
  • curl-debuginfo< 0:8.12.1-4.el10_2.4
  • curl-debugsource< 0:8.12.1-4.el10_2.4
  • libcurl< 0:8.12.1-4.el10_2.4
  • libcurl-debuginfo< 0:8.12.1-4.el10_2.4
Alpine1 product
  • curl≥ 7.12.0, < 8.14.1-r3 | ≥ 7.12.0, < 8.14.1-r4 | ≥ 7.12.0, < 8.22.0-r0 | ≥ 7.12.0, < 8.21.0-r0
Curl1 product
  • curl≥ 7.12.0, < 8.14.2 | ≥ 8.15.0, < 8.16.1 | ≥ 8.17.0, < 8.20.1 | ≥ fc6eff13b5414caf6edf22d73a3239e074a04216, < 5c225384b8d52c67ce8259c6e4203bc57aacb567 | 8.20.0 | 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 | 7.70.0 | 7.69.1 | 7.69.0 | 7.68.0 | 7.67.0 | 7.66.0 | 7.65.3 | 7.65.2 | 7.65.1 | 7.65.0 | 7.64.1 | 7.64.0 | 7.63.0 | 7.62.0 | 7.61.1 | 7.61.0 | 7.60.0 | 7.59.0 | 7.58.0 | 7.57.0 | 7.56.1 | 7.56.0 | 7.55.1 | 7.55.0 | 7.54.1 | 7.54.0 | 7.53.1 | 7.53.0 | 7.52.1 | 7.52.0 | 7.51.0 | 7.50.3 | 7.50.2 | 7.50.1 | 7.50.0 | 7.49.1 | 7.49.0 | 7.48.0 | 7.47.1 | 7.47.0 | 7.46.0 | 7.45.0 | 7.44.0 | 7.43.0 | 7.42.1 | 7.42.0 | 7.41.0 | 7.40.0 | 7.39.0 | 7.38.0 | 7.37.1 | 7.37.0 | 7.36.0 | 7.35.0 | 7.34.0 | 7.33.0 | 7.32.0 | 7.31.0 | 7.30.0 | 7.29.0 | 7.28.1 | 7.28.0 | 7.27.0 | 7.26.0 | 7.25.0 | 7.24.0 | 7.23.1 | 7.23.0 | 7.22.0 | 7.21.7 | 7.21.6 | 7.21.5 | 7.21.4 | 7.21.3 | 7.21.2 | 7.21.1 | 7.21.0 | 7.20.1 | 7.20.0 | 7.19.7 | 7.19.6 | 7.19.5 | 7.19.4 | 7.19.3 | 7.19.2 | 7.19.1 | 7.19.0 | 7.18.2 | 7.18.1 | 7.18.0 | 7.17.1 | 7.17.0 | 7.16.4 | 7.16.3 | 7.16.2 | 7.16.1 | 7.16.0 | 7.15.5 | 7.15.4 | 7.15.3 | 7.15.2 | 7.15.1 | 7.15.0 | 7.14.1 | 7.14.0 | 7.13.2 | 7.13.1 | 7.13.0 | 7.12.3 | 7.12.2 | 7.12.1 | 7.12.0
Debian1 product
  • curlAll versions (No fix recorded) | < 8.14.1-2+deb13u7 | < 8.21.0~rc2-1
Haxx1 product
  • curl≥ 7.12.0, < 8.21.0
Ubuntu1 product
  • curl< 7.35.0-1ubuntu2.20+esm20 | < 7.47.0-1ubuntu2.19+esm16 | < 7.58.0-2ubuntu3.24+esm9 | < 7.68.0-1ubuntu2.25+esm4 | < 7.81.0-1ubuntu1.25 | < 8.5.0-2ubuntu10.10 | < 8.14.1-2ubuntu1.4 | < 8.18.0-1ubuntu2.2
Wolfi1 product
  • libcurl4All versions (No fix recorded)

8 vendors · 25 products

References

17 links
Show all 17 references