CVE-2026-67339: guzzle
CVSS: 6.9v4.0MediumAwaiting analysis
AliasesUBUNTU-CVE-2026-67339DEBIAN-CVE-2026-67339CGA-4hjj-jhqx-58v8CGA-h3g3-7vm5-xcfcCGA-hx43-mfhg-wj3jCGA-xvw9-xw5q-xc6wCGA-4ph6-pwv5-wh24CGA-67p2-82x8-938hCGA-82j6-69gc-37r3CGA-ff3x-4c3h-6rrcCGA-m29m-vh9q-xgvhCGA-php9-xjr2-vp4vCGA-rjp4-654c-8xx4CGA-rvwr-mwxc-x3v5
Published 01-08-2026Last modified 08-10-2026
Vulnerability summary
CVE-2026-67339 is a medium (CVSS 6.9) vulnerability in guzzle. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 29.9% of scored vulnerabilities.
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)EPSS score
0.37%
0%100%
Low · +0.14 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 0 · Related 1Timeline
- 01-08-2026PublishedVulnerability first disclosed.
- 08-10-2026Last modifiedVulnerability information updated.
Description
guzzlehttp/guzzle versions before 7.14.2 fail to properly isolate Proxy-Authorization headers from origin servers in cURL handlers. Attackers can capture proxy credentials through origin server access logs when requests are redirected, bypassed, or sent through SOCKS proxies that Guzzle misclassifies as direct connections.
CVSS metrics
9 scores · 6 sources · 2 versionsMedium 6.9Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NSourcesAll 6 agree
- OSV · UbuntuEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · WolfiEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- NVDNIST6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Medium 5.3Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS trend
Probability
0.37%
Chance of exploitation in the next 30 days
Percentile
30%
Versus all other CVEs
30-day change
+0.14 pp
From 0.23% on 21-09-2026
21-09-202621-10-2026
EPSS score0.37%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Chainguard6 products
- drupal-11.3< 11.3.16-r0
- nextcloud-server-31< 31.0.14-r5
- nextcloud-server-32< 32.0.12-r6
- nextcloud-server-33< 33.0.6-r8
- nextcloud-server-34< 34.0.1-r9
Wolfi2 products
- nextcloud-server-32< 32.0.12-r6
- nextcloud-server-33< 33.0.6-r8
Debian1 product
- guzzleAll versions (No fix recorded) | < 7.14.2-1
Guzzle1 product
- guzzle< 7.14.2
Ubuntu1 product
- guzzleAll versions (No fix recorded)
5 vendors · 11 products
References
7 links- www.vulncheck.com/advisories/guzzlehttp-guzzle-before-proxy-authorization-header-disclosureThird Party AdvisoryREPORTAdvisory
