CVE-2026-26007
Missing Validation vulnerability in cryptography (PyPI)
What is CVE-2026-26007 About?
This vulnerability involves a missing validation in cryptographic functions related to elliptic curve public keys. It allows an attacker to provide a public key point from a small-order subgroup, leading to information leakage of private keys or easy signature forgery. Exploitation is moderately complex, requiring specialized knowledge of elliptic curve cryptography to craft malicious public keys.
Affected Software
Technical Details
The public_key_from_numbers (and related functions like EllipticCurvePublicNumbers.public_key(), load_der_public_key(), load_pem_public_key()) fail to verify that a provided public key point belongs to the expected prime-order subgroup of the elliptic curve. Attackers can exploit this by presenting a public key point P that resides in a small-order subgroup. In ECDH key negotiation, this allows the attacker to compute S = [victim_private_key]P, revealing bits of the victim_private_key modulo the small subgroup order, especially for curves with a cofactor greater than 1. When such weak public keys are used with ECDSA, it becomes significantly easier for an attacker to forge signatures by performing calculations within the small subgroup.
What is the Impact of CVE-2026-26007?
Successful exploitation may allow attackers to leak sensitive cryptographic information, such as portions of private keys, or forge digital signatures, compromising data integrity and authenticity.
What is the Exploitability of CVE-2026-26007?
Exploitation of this vulnerability requires a sophisticated understanding of elliptic curve cryptography and the specific SECT curves affected. Attackers would need to craft specific invalid public key points belonging to small-order subgroups. There are no authentication requirements to introduce these malformed public keys into a system that uses the vulnerable functions. Privilege requirements are low, as an attacker only needs the ability to submit a public key. The attack is remote, as it relies on manipulating input to cryptographic functions. The primary constraint is the attacker's ability to generate the specially crafted public keys and the target system's reliance on the affected SECT curve implementations. The likelihood of exploitation increases if systems are widely deployed using these specific SECT curves with the vulnerable cryptographic libraries.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2026-26007?
Available Upgrade Options
- cryptography
- <46.0.5 → Upgrade to 46.0.5
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Book a demoAdditional Resources
- https://github.com/pyca/cryptography
- https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c
- https://osv.dev/vulnerability/GHSA-r6ph-v2qm-q3c2
- https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2
- https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c
- http://www.openwall.com/lists/oss-security/2026/02/10/4
- https://github.com/pyca/cryptography/releases/tag/46.0.5
- https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2
What are Similar Vulnerabilities to CVE-2026-26007?
Similar Vulnerabilities: CVE-2023-40114 , CVE-2023-3817 , CVE-2023-34969 , CVE-2023-32697 , CVE-2023-28491
