CVE-2026-63499

Read full description

zt-zip is a Java library that provides convenience methods for ZIP archive manipulation. Prior to 1.18.1, ZipUtil.unpack(...) can apply stored ZIP-entry permissions to the extraction output directory when an entry name such as / or ./ resolves to that directory itself. Because the path traversal checks permit self-referencing entries that do not escape the destination, the unpacker's permission-handling path can replace restrictive output-directory permissions with attacker-supplied permissions. This affects applications that unpack untrusted ZIP files, and POSIX systems demonstrate the issue directly, while ZTFilePermissionsUtil.fetchDefaultStrategy provides fallback permission handling on other supported systems. This issue is fixed in version 1.18.1.

CVSS 6.9 (MEDIUM)

Attention and evidence

HYPE SCORE

0.0/10

REALITY · THREAT PRIORITY

2.4/10

General review priority; not probability

Evidence confidence: Insufficient evidence

Why this priority?

Technical severity: CVSS 6.9: +2.42
Fresh EPSS: 0.28%: +0.01

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 1 documents and public datasets.

Hype components

Headline sample (25%)

0/100

Press, 30 days (60%)

0/100

Grounded branding (15%)

0/100

HYPE TOTAL0/100

Sources and documents

Latest Vulnerabilities

Technical advisory · 03 Nov 2026, 18:18 · CVE-2026-63499 - zt-zip: ZipUtil.unpack can change file permissions of output directory

Score evolution

● Hype ● Reality

━ Hype Score (Perceived) ━ Reality threat priority. Definition changes are not new attacks.

Public exploit evidence

Public exploit entries / repo candidates

Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs. Published 4 days ago. Exploitation evidence usually takes weeks to show up: a low reality score can mean there is no data yet, not that the flaw is mild.

Evidence in context

Confidence in exploitation evidence: Insufficient evidence
Priority basis: Exploitation in attacks unconfirmed; CVSS 6.9; EPSS 0.3%
Attention, last 30 days: 0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential: local access, no prior privileges, passive user interaction.
Observed activity: No exploitation observation is recorded.
Known scale: Not quantified.
Evidence confidence basis: Insufficient evidence

Score evaluated: 2026-11-05 14:00:19.801232+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline

Published

03 Nov 2026, 18:04

Score calculated

05 Nov 2026, 14:00