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Fencer Intel
medium 5.5

CVE-2021-23521 json

Link Following

published 4y ago modified 4mo ago also EUVD-2021-10488

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

This affects the package juce-framework/JUCE before 6.1.5. This vulnerability is triggered when a malicious archive is crafted with an entry containing a symbolic link. When extracted, the symbolic link is followed outside of the target dir allowing writing arbitrary files on the target host. In some cases, this can allow an attacker to execute arbitrary code. The vulnerable code is in the ZipFile::uncompressEntry function in juce_ZipFile.cpp and is executed when the archive is extracted upon calling uncompressTo() on a ZipFile object.

Patch / fix

  • juce juce 6.1.5
  • juce Debian 14, Debian 13, Debian 12 6.1.5~ds0-1

debian advisories DEBIAN-CVE-2021-23521

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Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-UNMANAGED-JUCEFRAMEWORKJUCE-2388608 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-59 Improper Link Resolution Before File Access

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.