Skip to content
Noroxi
CVE-2023-23931· NVD / CVE Program· CNA GitHub_M

Cipher.update_into can corrupt memory in pyca cryptography

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.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Feb 7, 2023
Updated
Jun 17, 2026
EPSS
1.3% · 69th percentile
Follow this CVE

Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.3%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
4.8
1.7 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
cryptography.iocryptography

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cryptography.io cryptography1.8 and later · before 39.0.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • pyca cryptography

    • >=1.8, < 39.0.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8python3-cryptographybefore 3.2.1-6.el83.2.1-6.el8
AlmaLinux:8python39before 3.9.18-3.module_el8.10.0+3765+2f9a457d3.9.18-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-attrsbefore 20.3.0-2.module_el8.6.0+2780+a40f65e120.3.0-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-cffibefore 1.14.3-2.module_el8.6.0+2780+a40f65e11.14.3-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-cffibefore 1.14.3-2.module_el8.6.0+3248+c431e88c1.14.3-2.module_el8.6.0+3248+c431e88c
AlmaLinux:8python39-chardetbefore 3.0.4-19.module_el8.6.0+2780+a40f65e13.0.4-19.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-cryptographybefore 3.3.1-3.module_el8.10.0+3765+2f9a457d3.3.1-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-Cythonbefore 0.29.21-5.module_el8.6.0+3248+c431e88c0.29.21-5.module_el8.6.0+3248+c431e88c
AlmaLinux:8python39-Cythonbefore 0.29.21-5.module_el8.6.0+2780+a40f65e10.29.21-5.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-debugbefore 3.9.18-3.module_el8.10.0+3765+2f9a457d3.9.18-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-develbefore 3.9.18-3.module_el8.10.0+3765+2f9a457d3.9.18-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-idlebefore 3.9.18-3.module_el8.10.0+3765+2f9a457d3.9.18-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-idnabefore 2.10-3.module_el8.6.0+2780+a40f65e12.10-3.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-iniconfigbefore 1.1.1-2.module_el8.6.0+2780+a40f65e11.1.1-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-libsbefore 3.9.18-3.module_el8.10.0+3765+2f9a457d3.9.18-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-lxmlbefore 4.6.5-1.module_el8.6.0+3248+c431e88c4.6.5-1.module_el8.6.0+3248+c431e88c
AlmaLinux:8python39-lxmlbefore 4.6.5-1.module_el8.6.0+2780+a40f65e14.6.5-1.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-mod_wsgibefore 4.7.1-7.module_el8.9.0+3634+fb2a896c4.7.1-7.module_el8.9.0+3634+fb2a896c
AlmaLinux:8python39-more-itertoolsbefore 8.5.0-2.module_el8.6.0+2780+a40f65e18.5.0-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-numpybefore 1.19.4-3.module_el8.6.0+2780+a40f65e11.19.4-3.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-numpybefore 1.19.4-3.module_el8.6.0+3248+c431e88c1.19.4-3.module_el8.6.0+3248+c431e88c
AlmaLinux:8python39-numpy-docbefore 1.19.4-3.module_el8.6.0+2780+a40f65e11.19.4-3.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-numpy-f2pybefore 1.19.4-3.module_el8.6.0+2780+a40f65e11.19.4-3.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-numpy-f2pybefore 1.19.4-3.module_el8.6.0+3248+c431e88c1.19.4-3.module_el8.6.0+3248+c431e88c

+96

Other highest-scoring records for the same primary product.

  • CVE-2020-36242In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result
    38Monitor
  • CVE-2026-26007cryptography Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
    32Monitor
  • CVE-2016-9243HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.
    31Monitor
  • CVE-2024-26130cryptography NULL pointer deference with pkcs12.serialize_key_and_certificates when called with a non-matching certificate and private key and an hmac_hash over
    30Monitor
  • CVE-2023-49083cryptography vulnerable to NULL-dereference when loading PKCS7 certificates
    30Monitor
  • CVE-2023-38325The cryptography package before 41.0.2 for Python mishandles SSH certificates that have critical options.
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:python3-cryptography36.0.1-4.el9 · AlmaLinux:9Package registry (OSV)
almalinux:python393.9.18-3.module_el8.10.0+3765+2f9a457d · AlmaLinux:8Package registry (OSV)
almalinux:python39-attrs20.3.0-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8Package registry (OSV)
almalinux:python39-cffi1.14.3-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8Package registry (OSV)
almalinux:python39-chardet3.0.4-19.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8Package registry (OSV)
almalinux:python39-cryptography3.3.1-3.module_el8.10.0+3765+2f9a457d · AlmaLinux:8Package registry (OSV)
almalinux:python39-Cython0.29.21-5.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8Package registry (OSV)
almalinux:python39-debug3.9.18-3.module_el8.10.0+3765+2f9a457d · AlmaLinux:8Package registry (OSV)
almalinux:python39-devel3.9.18-3.module_el8.10.0+3765+2f9a457d · AlmaLinux:8Package registry (OSV)
almalinux:python39-idle3.9.18-3.module_el8.10.0+3765+2f9a457d · AlmaLinux:8Package registry (OSV)
almalinux:python39-idna2.10-3.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8Package registry (OSV)
almalinux:python39-PyMySQL0.10.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8Package registry (OSV)
alpine:py3-cryptography39.0.1-r0 · Alpine:v3.23Package registry (OSV)
debian:python-cryptography38.0.4-3 · Debian:12Package registry (OSV)
opensuse:python-cryptography3.3.2-150400.16.6.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
PyPI:cryptography39.0.1Package registry (OSV)
red hat:automation-eda-controller0:1.0.1-1.el8ap · Red Hat:ansible_automation_platform:2.4::el8Package registry (OSV)
red hat:automation-eda-controller-server0:1.0.1-1.el8ap · Red Hat:ansible_automation_platform:2.4::el8Package registry (OSV)
red hat:automation-eda-controller-ui0:1.0.1-1.el8ap · Red Hat:ansible_automation_platform:2.4::el8Package registry (OSV)
red hat:python-cryptography0:38.0.4-2.el9ap · Red Hat:ansible_automation_platform_developer:2.4::el9Package registry (OSV)
red hat:python-cryptography-debugsource0:38.0.4-2.el9ap · Red Hat:ansible_automation_platform_developer:2.4::el9Package registry (OSV)
red hat:python3-cryptography0:38.0.4-2.el9ap · Red Hat:ansible_automation_platform_developer:2.4::el9Package registry (OSV)
red hat:python3-cryptography-debuginfo0:38.0.4-2.el9ap · Red Hat:ansible_automation_platform_developer:2.4::el9Package registry (OSV)
red hat:python39-cryptography0:38.0.4-2.el8ap · Red Hat:ansible_automation_platform_developer:2.4::el8Package registry (OSV)
red hat:python39-cryptography-debuginfo0:38.0.4-2.el8ap · Red Hat:ansible_automation_platform_developer:2.4::el8Package registry (OSV)
red hat:python39-requests0:2.31.0-1.el8ap · Red Hat:ansible_automation_platform:2.4::el8Package registry (OSV)
red hat:python3x-cryptography0:38.0.4-2.el8ap · Red Hat:ansible_automation_platform_developer:2.4::el8Package registry (OSV)
red hat:python3x-cryptography-debugsource0:38.0.4-2.el8ap · Red Hat:ansible_automation_platform_developer:2.4::el8Package registry (OSV)
rocky linux:Cython0:0.29.21-5.module+el8.10.0+1582+bc278001 · Rocky Linux:8Package registry (OSV)
rocky linux:mod_wsgi0:4.7.1-7.module+el8.10.0+1582+bc278001 · Rocky Linux:8Package registry (OSV)

+21

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
low · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

All records