CVE-2026-27820
critical
CVSS v3
9.8
CVSS v4 NEW
1.7
VIR risk
9.8
Description
Buffer Overflow in Zlib::GzipReader ungetc via large input leads to memory corruption
Predictions
Exploit likelihood
97%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Debian Affected 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Affected | — |
| forky | Affected | — |
| bullseye | Affected | — |
| bookworm | Affected | — |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| ruby-lang | zlib | {"endExcluding":"3.0.1"} | 3.0.1 |
References
- https://www.ruby-lang.org/en/news/2026/03/05/buffer-overflow-zlib-cve-2026-27820
- https://github.com/ruby/zlib/security/advisories/GHSA-g857-hhfv-j68w
- https://hackerone.com/reports/3467067
- https://www.suse.com/security/cve/CVE-2026-27820.html
- https://nvd.nist.gov/vuln/detail/CVE-2026-27820
- https://github.com/ruby/zlib
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/zlib/CVE-2026-27820.yml
- https://security-tracker.debian.org/tracker/CVE-2026-27820
CWEs
CWE-120 CWE-131
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.