GHSA-w7pp-m8wf-vj6r: cryptography (CVE-2023-23931)

Package	Ecosystem	Affected	Fixed in
cryptography	PyPI	>=1.8, <39.0.1	39.0.1

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Cryptography versions from 1.8 up to but not including 39.0.1 are affected: Cipher.update_into would accept immutable buffer objects such as bytes as its output buffer, allowing them to be mutated. An attacker cannot exploit this with attacker-controlled data alone; it requires a programmer to misuse the API. Upgrade to cryptography 39.0.1 or later, which raises an exception in this case.

Written 5 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
4.8	Medium	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.013, the 70th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

7 Feb 2023, 19:48 UTC Published by the maintainers as a GitHub repository advisory
31 Oct 2026, 14:37 UTC First seen by agentprime
31 Oct 2026, 14:37 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.