# CVE-2026-69249 — pyca cryptography

> As of 2026-08-04, CVE-2026-69249 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in pyca cryptography, CVSS v4.0 8.7, EPSS 0.1% (9.1th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-69249 as of 2026-08-04; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-04

## What is CVE-2026-69249?

python-cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to 49.0.0, 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.

The record classifies CVE-2026-69249 under weakness class [CWE-400](https://intel.threadlinqs.com/cwe/CWE-400). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 63 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.7 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 9.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-03, last modified 2026-08-04

## Is CVE-2026-69249 being exploited?

It currently carries a trending score of 32 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **pyca**: cryptography

Affected software packages:

- `pip:cryptography` — patched in 49.0.0

## How to fix CVE-2026-69249

Fixed versions are recorded for 1 package: pip:cryptography 49.0.0. No vendor patch reference has been recorded for CVE-2026-69249 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-69249

No threat campaign in the Threadlinqs corpus currently references CVE-2026-69249, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, GitHub Security Advisories, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-08-05. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/pyca/cryptography/security/advisories/GHSA-jwv3-5hgf-82ww)

**Other references**

- [github.com](https://github.com/pyca/cryptography/pull/14960)
- [github.com (4a12cf49675a184e47f912b00b04f3a629283582)](https://github.com/pyca/cryptography/commit/4a12cf49675a184e47f912b00b04f3a629283582)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-69249
Full detection coverage and IOCs for threats exploiting CVE-2026-69249 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp