python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 6 fixed, 3 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.
Summary
python-cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In versions 42.0.0 through 48.0.0, when resolving invalid certificate chains that include duplicate copies of self-signed certificates, the processing recursively invokes the same candidate, leading to an exponential blowup. Although the limitation that the chain depth cannot exceed a specified maximum depth prevents unbounded recursion and guarantees termination, an attacker-controlled certificate chain can lead the processing to easily take more than 5s to reject in testing. This amplification could form the basis for a resource exhaustion denial of service attack. The core issue arises in the recursive nature of build_chain_inner, which does not de-duplicate against previously analyzed candidates. As the correctness of validation is not affected, the integrity of a system cannot be compromised through this vector, only its availability. This issue is fixed in 49.0.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| pyca | cryptography | 42.0.0 to before 49.0.0 | 49.0.0 | Patch available | CNA |
| — | cryptography (PyPI) | 42.0.0 to before 49.0.0 | 49.0.0 | Patch available | GHSA-jwv3-5hgf-82ww |
- cryptography Vendorpyca Affected 42.0.0 to before 49.0.0 Fixed in 49.0.0 Patch available CNA
- cryptography (PyPI) Vendor— Affected 42.0.0 to before 49.0.0 Fixed in 49.0.0 Patch available GHSA-jwv3-5hgf-82ww
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:cryptography.io:cryptography:*:*:*:*:*:*:*:* | — | — | Cryptography.io |
- cpe:2.3:a:cryptography.io:cryptography:*:*:*:*:*:*:*:* Versions — — ·Cryptography.io
Remediation
- Fix · CNA cryptography (pyca) Fixed in 49.0.0
- Fix · GHSA-jwv3-5hgf-82ww cryptography (PyPI) Fixed in 49.0.0 Advisory →
Red Hat 9 advisories
- RHSA-2026:71658 Released 2026-09-24 · Red Hat rating Importantpython-cryptography security update
- Red Hat Enterprise Linux BaseOS (v. 10) python-cryptography-43.0.0-4.el10_2.5, python3-cryptography-43.0.0-4.el10_2.5
- RHSA-2026:71659 Released 2026-09-24 · Red Hat rating Importantpython-cryptography security update
- Red Hat Enterprise Linux BaseOS EUS (v. 10.0) python-cryptography-43.0.0-4.el10_0.1, python3-cryptography-43.0.0-4.el10_0.1
- RHSA-2026:70995 Released 2026-09-23 · Red Hat rating ImportantRed Hat AI Inference 3.4.5 (rocm)
- Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-rocm-rhel9
Show 6 more Red Hat advisories
- RHSA-2026:70979 Released 2026-09-23 · Red Hat rating ImportantRed Hat AI Inference 3.4.5 (cuda)
- Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cuda-rhel9
- RHSA-2026:70969 Released 2026-09-23 · Red Hat rating ImportantRed Hat AI Inference 3.4.5 (spyre)
- Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-spyre-rhel9
- RHSA-2026:70965 Released 2026-09-23 · Red Hat rating ImportantRed Hat AI Inference 3.4.5 (cpu)
- Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cpu-rhel9
- RHSA-2026:64795 Released 2026-09-08 · Red Hat rating Importantpython3.14-cryptography security update
- Red Hat Enterprise Linux AppStream (v. 10) python3.14-cryptography-45.0.4-4.el10_2.5
- RHSA-2026:64774 Released 2026-09-08 · Red Hat rating Importantpython3.14-cryptography security update
- Red Hat Enterprise Linux AppStream (v. 9) python3.14-cryptography-45.0.4-4.el9_8.6
- RHSA-2026:55543 Released 2026-08-17 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images python-cryptography-50.0.0-1.hum1@src, python3-cryptography-50.0.0-1.hum1@aarch64, python3-cryptography-50.0.0-1.hum1@x86_64
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet |
| Red Hat Satellite 6 | Affected | No fix yet |
| Red Hat AI Inference Server 3.4 | Fixed | RHSA-2026:70965, RHSA-2026:70969, RHSA-2026:70979, RHSA-2026:70995 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:64795 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:64774 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:71658 |
| Red Hat Enterprise Linux BaseOS EUS (v. 10.0) | Fixed | RHSA-2026:71659 |
| Red Hat Hardened Images | Fixed | RHSA-2026:55543 |
Not affected: 7 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
- Red Hat OpenStack Platform 13 (Queens)
- Red Hat Update Infrastructure 4 for Cloud Providers
Timeline
- 2026-10-02 Threatist record created from CVE-2026-69249
- 2026-10-03 Alias added: GHSA-jwv3-5hgf-82ww
- 2026-10-08 Affected versions changed · Red Hat
- 2026-10-16 Affected versions changed · Red Hat
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
Other 6
- https://github.com/pyca/cryptography/security/advisories/GHSA-jwv3-5hgf-82ww
- https://github.com/pyca/cryptography/pull/14960
- https://github.com/pyca/cryptography/commit/3763aa79b
- https://github.com/pyca/cryptography/commit/4a12cf49675a184e47f912b00b04f3a629283582
- https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-3553.yaml
- https://github.com/pyca/cryptography
More pyca vulnerabilities
- TI-2026-48587 python-cryptography verifier accepts wildcard DNS names allowing escape from permittedSubtrees CVSS 4.0MEDIUM 6.9
- TI-2026-48586 cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing CVSS 4.0HIGH 8.2
Sources
- CVE-2026-69249 · CVE Program
- CVE-2026-69249 · NVD
- FIRST EPSS
- GHSA-jwv3-5hgf-82ww · GitHub Advisory Database · CC BY 4.0
- CVE-2026-69249 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences