#VU29439 Out-of-bounds read in Pillow - CVE-2020-10378

Vulnerability identifier: #VU29439

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-10378

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Pillow
Universal components / Libraries / Libraries used by multiple products

Vendor: Alex Clark and Contributors

Description

The vulnerability allows a remote attacker to perform a denial of service attack.

The vulnerability exists due to an out-of-bounds read in "libImaging/PcxDecode.c" that occurs when reading PCX files where state->shuffle is instructed to read beyond state->buffer. A remote attacker can create a specially crafted PCX file, trick the victim into opening it, trigger out-of-bounds read error and read contents of memory on the system. 

Mitigation
Install update from vendor's website.

Vulnerable software versions

Pillow: 6.2.0 - 7.0.0

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External links
https://github.com/python-pillow/Pillow/commit/6a83e4324738bb0452fbe8074a995b1c73f08de7#diff-9478f2787e3ae9668a15123b165c23ac
https://github.com/python-pillow/Pillow/commits/master/src/libImaging
https://github.com/python-pillow/Pillow/pull/4538
https://pillow.readthedocs.io/en/stable/releasenotes/6.2.3.html
https://pillow.readthedocs.io/en/stable/releasenotes/7.1.0.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.