CVE-2026-85396: rubyzip before 3.4.0 Path Traversal in Zip::Entry#extract via Sibling-Directory Prefix
Awaiting analysis
AliasesUBUNTU-CVE-2026-85396DEBIAN-CVE-2026-85396CGA-37pf-5mcx-jqpmCGA-5p38-j4mx-37hrCGA-63c6-5xj7-jg69CGA-7846-gjwf-vx2gCGA-88f2-mqv7-9vrgCGA-9m2p-59mj-3w74CGA-j5fx-mjgg-mf49CGA-rg39-8c65-3p75CGA-whch-mg3w-83c8CGA-x2xf-r68f-7896CGA-22x8-6388-4gxjCGA-25hv-w65w-4qm6CGA-27f9-g8rr-xx28CGA-2jpv-hrgp-29f3CGA-2m4c-cjm9-wcmhCGA-2xrj-3rp5-86j7CGA-376f-h5j9-ghm6CGA-3gw4-55fm-p3w9CGA-3jhj-fjp2-54xqCGA-3wvp-w4hm-g5pgCGA-4vcf-7rmg-4f4hCGA-52j2-m7g8-c665CGA-5332-jg64-h274CGA-574f-8qrx-gwqhCGA-5fww-jv54-pm2rCGA-5g3v-q9j9-wxxrCGA-5hpr-8v5f-5pjmCGA-5rf9-rx6c-mghhCGA-67cr-6fj4-3v3jCGA-6hg8-rgpq-8r8vCGA-6wf6-9hqp-6jfhCGA-736f-h75x-8w87CGA-75cm-3mw2-4qv2CGA-7hjj-px8r-5qm9CGA-7pqj-65jc-478wCGA-7r9c-cv37-f8gfCGA-82vw-78h7-75h3CGA-9cjm-7w22-f2xjCGA-9fpg-47pv-fr8wCGA-9h4j-r96j-rgjfCGA-9p2h-fqg4-qc69CGA-9pgw-rjjh-2j3gCGA-c3xv-cw62-w376CGA-c98c-8h59-47jpCGA-cmr7-hwmm-rw7hCGA-cwjj-m8r9-rfvqCGA-f8qr-2q5f-7vpmCGA-fr73-f2p3-p5w5CGA-fw67-cx4v-36jpCGA-g498-v6xp-v28mCGA-g4x5-8pqf-5gcjCGA-g4xw-9xwj-wv9vCGA-h2mq-wwjr-8q5hCGA-h88p-vh42-5865CGA-hg4v-563q-w4gvCGA-hg8g-55g7-h5x6CGA-hq35-3679-g2rwCGA-hxrf-54m8-9cqgCGA-m9hq-xfqq-m3xwCGA-mm38-fx5f-64rwCGA-p9xw-6c5q-c598CGA-pg89-fw4h-pvjmCGA-pv9g-mrxr-3v9wGHSA-47m2-wp7j-p9vcCGA-qqx3-4h6q-7xm9CGA-rf7j-jcpx-7jp4CGA-rhgc-rjx7-j734CGA-rmvf-858r-j4rvCGA-v588-hvhp-pgp4CGA-v9j2-q33f-p58xCGA-vgxc-384h-h8r8CGA-vhgq-m93p-gfqgCGA-vqc8-p646-33g3CGA-vr8p-6986-95fvCGA-vxhr-pc9m-4w27CGA-w29x-x234-qg78CGA-w5fg-r369-9pc9CGA-wgjm-qvr3-8mf6CGA-ww6r-j38r-q6rgCGA-xjh5-92wm-fpggCGA-xmh9-q27x-2gf5CGA-f6h8-44rq-g8vwCGA-qx49-5p6h-j6wfCGA-vhrh-mwvv-38gqCGA-pvqw-82qj-cp4vCGA-rrqv-w72g-79wwCGA-x426-f29h-r7w2CGA-c3cw-c8hw-qcwfCGA-j523-h6fw-crh2CGA-ww25-qg4w-4mcwCGA-xfgp-2cw7-4ff7
Published 03-09-2026Last modified 03-09-2026
Vulnerability summary
CVE-2026-85396 is a high (CVSS 8.7) vulnerability in rubyzip. EPSS estimates a 0.56% chance of exploitation in the next 30 days, higher than 46.9% of scored vulnerabilities.
Priority
Prioritisesevere
Severe, CVSS 8.7 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?CVSS score
8.7/10
010
High · v4.0 (CVE.org)EPSS score
0.56%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded
Timeline
- 03-09-2026PublishedVulnerability first disclosed.
- 03-09-2026Last modifiedVulnerability information updated.
Description
rubyzip versions before 3.4.0 contain a path traversal vulnerability in Zip::Entry#extract that fails to properly validate extraction paths using prefix comparison without trailing separators. Attackers can craft archive entries with names like ../upload_backup/owned.sh to write files outside the intended extraction directory into sibling paths sharing the destination prefix.
CVSS metrics
11 scores · 7 sources · 2 versionsHigh 8.7Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NSourcesAll 6 agree
- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- OSV · WolfiEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- OSV · RubygemsEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- NVDNIST8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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
High 7.5Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NSourcesAll 5 agree
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · RubygemsEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS trend
Probability
0.56%
Chance of exploitation in the next 30 days
Percentile
47%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.56% on 04-10-2026
04-10-202603-11-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Version check
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard45 products
- cinc-auditorAll versions (No fix recorded) | < 7.1.7-r8
- commercial-gitlab-rails-ee-19.1All versions (No fix recorded)
- commercial-gitlab-rails-ee-19.2All versions (No fix recorded)
- commercial-gitlab-rails-ee-19.3All versions (No fix recorded)
- commercial-gitlab-rails-ee-19.4All versions (No fix recorded)
Wolfi5 products
- cinc-auditorAll versions (No fix recorded) | < 7.1.7-r8
- logstash-9.3All versions (No fix recorded)
- logstash-9.3-iamguarded-compatAll versions (No fix recorded)
- logstash-9.4All versions (No fix recorded) | < 9.4.8-r0
- logstash-9.4-iamguarded-compatAll versions (No fix recorded) | < 9.4.8-r0
Debian1 product
- ruby-zipAll versions (No fix recorded) | < 3.4.0+dfsg-1
RubyGems1 product
- rubyzip< 3.4.0
Rubyzip1 product
- rubyzip< 3.4.0
Ubuntu1 product
- ruby-zipAll versions (No fix recorded)
6 vendors · 54 products
