CVE-2026-69249
published 2026-08-03CVE-2026-69249: 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…
PriorityP347high8.7CVSS 4.0
AVNACLATNPRNUINVCNVINVAHSCNSINSANEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.25%
15.8th percentile
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.
Affected
6 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| cryptography.io | cryptography | >= 0 < 49.0.0 | 49.0.0 |
| debian | python-cryptography | — | — |
| pyca | cryptography | — | — |
| rhel10 | keylime-registrar | — | — |
| rhel10 | keylime-verifier | — | — |
| ubuntu | python-cryptography | — | — |
CVSS provenance
nvdv4.08.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat8.7HIGH
vendor_ubuntu6.5MEDIUM
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Ubuntu
python-cryptography vulnerabilities
vendor_ubuntu·2026-09-16·CVSS 6.5
CVE-2026-69249 [MEDIUM] python-cryptography vulnerabilities
Title: python-cryptography vulnerabilities
Summary: Several security issues were fixed in python-cryptography.
It was discovered that python-cryptography incorrectly accepted objects
with immutable buffers when performing certain cipher operations. This
would result in corrupted output, contrary to expectations. This issue only
affected Ubuntu 18.04 LTS. (CVE-2023-23931)
It was discovered that python-cryptography reported the outcome of
decrypting PKCS#7 enveloped data in distinguishable ways, and with
observable timing differences. A remote attacker could possibly use this
issue to recover the key used to encrypt the message contents, and obtain
sensitive information. This issue only affected Ubuntu 26.04 LTS.
(CVE-2026-69247)
Jack Lloyd discovered that python-cryptography incorrectly
Red Hat
python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
vendor_redhat·2026-08-03·CVSS 8.7
CVE-2026-69249 [HIGH] CWE-770 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
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 ari
VulDB
pyca cryptography up to 48.x build_chain_inner resource consumption
vuldb·2026-08-03·CVSS 8.7
CVE-2026-69249 [HIGH] pyca cryptography up to 48.x build_chain_inner resource consumption
A vulnerability has been found in pyca cryptography up to 48.x and classified as problematic. The impacted element is the function build_chain_inner. Performing a manipulation results in resource consumption.
This vulnerability is cataloged as CVE-2026-69249. It is possible to initiate the attack remotely. There is no exploit available.
The affected component should be upgraded.
GHSA
python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
ghsa·2026-08-03
CVE-2026-69249 [HIGH] CWE-400 python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
### Summary
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.
This work was completed by Trail of Bits as part of the Patch The Planet project in collaboration with OpenAI. The finding was identified primarily by the
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-69249 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building [fedora-all]
bugzilla·2026-10-07·CVSS 8.7
CVE-2026-69249 [HIGH] CVE-2026-69249 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building [fedora-all]
CVE-2026-69249 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
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
Bugzilla
CVE-2026-69249 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
bugzilla·2026-08-03·CVSS 8.7
CVE-2026-69249 [HIGH] CVE-2026-69249 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
CVE-2026-69249 python-cryptography: python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
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
https://github.com/pyca/cryptography/commit/3763aa79bhttps://github.com/pyca/cryptography/commit/4a12cf49675a184e47f912b00b04f3a629283582https://github.com/pyca/cryptography/pull/14960https://github.com/pyca/cryptography/security/advisories/GHSA-jwv3-5hgf-82wwhttps://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-3553.yamlhttps://github.com/pyca/cryptography/security/advisories/GHSA-jwv3-5hgf-82ww
2026-08-03
Published