CVE-2026-27171

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.24% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 15.9% of scored records. A rank, not a probability.

NVD base score

5.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

Low. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-02-18 02:36Z8 MO AGO

Last updated

2026-02-18 13:38Z8 MO AGO

Reserved

2026-02-18

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Low (CVSS 2.9)

CNA CVSS vector

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Weaknesses

• CWE-1284Improper Validation of Specified Quantity in InputBase
• CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')Base

Data version

5.2

Document digest

0f92ec672ae169dfb0464eaae638539fa02607c0c66c74ac637841affa683e13

• github.comhttps://github.com/madler/zlib/issues/904
• 7asecurity.comhttps://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf
• 7asecurity.comhttps://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/
• ostif.orghttps://ostif.org/zlib-audit-complete/
• github.comhttps://github.com/madler/zlib/releases/tag/v1.3.2