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Fencer Intel
medium 5.5

CVE-2018-20251 json

In WinRAR versions prior to and including 5.61, there is path traversal vulnerability when crafting the filename field of the ACE format.

published 7y ago modified 4mo ago also EUVD-2018-12814

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
31.4%
EPSS 31.4% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

In WinRAR versions prior to and including 5.61, there is path traversal vulnerability when crafting the filename field of the ACE format. The UNACE module (UNACEV2.dll) creates files and folders as written in the filename field even when WinRAR validator noticed the traversal attempt and requestd to abort the extraction process. the operation is cancelled only after the folders and files were created but prior to them being written, therefore allowing the attacker to create empty files and folders everywhere in the file system.

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Exploit prediction

31.40% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • research.checkpoint.com https://research.checkpoint.com/extracting-code-execution-from-winrar/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

  • Check Point Software Technologies Ltd. WinRAR

Classification

Weakness
  • CWE-693 Protection Mechanism Failure
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.