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Bug 866386 (CVE-2021-4217) - app-arch/unzip: null pointer dereference
Summary: app-arch/unzip: null pointer dereference
Alias: CVE-2021-4217
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal major (vote)
Assignee: Gentoo Security
Whiteboard: A2 [upstream]
Depends on:
Reported: 2022-08-24 18:57 UTC by John Helmert III
Modified: 2023-10-08 10:13 UTC (History)
1 user (show)

See Also:
Package list:
Runtime testing required: ---


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Description John Helmert III archtester Gentoo Infrastructure gentoo-dev Security 2022-08-24 18:57:31 UTC

A flaw was found in unzip. The vulnerability occurs due to improper handling of Unicode strings, which can lead to a null pointer dereference. This flaw allows an attacker to input a specially crafted zip file, leading to a crash or code execution.

Not sure if Ubuntu is the upstream here, or if there's any patch.
Comment 1 Larry the Git Cow gentoo-dev 2022-08-25 02:20:06 UTC
The bug has been referenced in the following commit(s):

commit bff42a923fb9b8ce5af167cc3032420d4a666307
Author:     Sam James <>
AuthorDate: 2022-08-25 02:18:16 +0000
Commit:     Sam James <>
CommitDate: 2022-08-25 02:19:14 +0000

    app-arch/unzip: add 6.0_p27
    Contains patches for CVE-2022-0529, CVE-2022-0530 (bug 831190) and
    for a unicode issue which *might* be CVE-2021-4217 (bug 866386).
    Signed-off-by: Sam James <>

 app-arch/unzip/Manifest             |  1 +
 app-arch/unzip/unzip-6.0_p27.ebuild | 93 +++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+)
Comment 2 Sam James archtester Gentoo Infrastructure gentoo-dev Security 2022-08-25 02:23:42 UTC
I saw this in Debian's changelog:
unzip (6.0-27) unstable; urgency=medium

  * Apply upstream patch for CVE-2022-0529 and CVE-2022-0530.
  - Fix null pointer dereference on invalid UTF-8 input.
  - Fix wide string conversion in process.c.
    Closes: #1010355.

But I don't think it's related to this bug, I'd misread it (it's all to do with bug 831190).

Nobody (Ubuntu, Debian, RH) have patched this, so no idea if htere's even a fix out there.