CVE-2023-23931
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In affected versions `Cipher.update_into` would accept Python objects which implement the buffer protocol, but provide only immutable buffers. This would allow immutable objects (such as `bytes`) to be mutated, thus violating fundamental rules of Python and resulting in corrupted output. This now correctly raises an exception. This issue has been present since `update_into` was originally introduced in cryptography 1.8.
02 / AFFECTED SOFTWARE
Affected packages
24 explicit affected versions
61 explicit affected versions
61 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In affected versions `Cipher.update_into` would accept Python objects which implement the buffer protocol, but provide only immutable buffers. This would allow immutable objects (such as `bytes`) to be mutated, thus violating fundamental rules of Python and resulting in corrupted output. This now correctly raises an exception. This issue has been present since `update_into` was originally introduced in cryptography 1.8.
Previously, `Cipher.update_into` would accept Python objects which implement the buffer protocol, but provide only immutable buffers: ```pycon >>> outbuf = b"\x00" * 32 >>> c = ciphers.Cipher(AES(b"\x00" * 32), modes.ECB()).encryptor() >>> c.update_into(b"\x00" * 16, outbuf) 16 >>> outbuf b'\xdc\x95\xc0x\xa2@\x89\x89\xadH\xa2\x14\x92\x84 \x87\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' ``` This would allow immutable objects (such as `bytes`) to be mutated, thus violating fundamental rules of Python. This is a soundness bug -- it allows programmers to misuse an API, it cannot be exploited by attacker controlled data alone. This now correctly raises an exception. This issue has been present since `update_into` was originally introduced in cryptography 1.8.
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In affected versions `Cipher.update_into` would accept Python objects which implement the buffer protocol, but provide only immutable buffers. This would allow immutable objects (such as `bytes`) to be mutated, thus violating fundamental rules of Python and resulting in corrupted output. This now correctly raises an exception. This issue has been present since `update_into` was originally introduced in cryptography 1.8.
05 / REFERENCES
Further evidence
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/23xxx/CVE-2023-23931.json
- https://github.com/pyca/cryptography/pull/8230/commits/94a50a9731f35405f0357fa5f3b177d46a726ab3
- https://github.com/pyca/cryptography/security/advisories/GHSA-w7pp-m8wf-vj6r
- https://lists.debian.org/debian-lts-announce/2024/10/msg00012.html
- https://nvd.nist.gov/vuln/detail/CVE-2023-23931
- https://security.netapp.com/advisory/ntap-20230324-0007/
- https://github.com/pyca/cryptography
- https://github.com/pyca/cryptography/commit/d6951dca25de45abd52da51b608055371fbcde4e
- https://github.com/pyca/cryptography/pull/8230
- https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2023-11.yaml
- https://security.netapp.com/advisory/ntap-20230324-0007