medium CVSS 6.5

CVE-2026-26007·Python vulnerability

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to 46.0.5, the public_key_from_numbers (or EllipticCurvePublicNumbers.public_key()), EllipticCurvePublicNumbers.public_key(), load_der_public_key() and load_pem_public_key() functions do not verify that the point belongs to the expected prime-order subgroup of the curve. This missing validation allows an attacker to provide a public key point P from a small-order subgroup. This can lead to security issues in various situations, such as the most commonly used signature verification (ECDSA) and shared key negotiation (ECDH). When the victim computes the shared secret as S = [victim_private_key]P via ECDH, this leaks information about victim_private_key mod (small_subgroup_order). For curves with cofactor > 1, this reveals the least significant bits of the private key. When these weak public keys are used in ECDSA , it's easy to forge signatures on the small subgroup. Only SECT curves are impacted by this. This vulnerability is fixed in 46.0.5.

Severity
medium
Software
Python
Fixed in
46.0.5
Published
2026-02-10

Affected versions

Until: 46.0.5

Fixed in: 46.0.5

How to fix this CVE

Update the Python cryptography library to version 46.0.5 or later to patch the elliptic curve point validation vulnerability. This fix ensures that public key points are verified to belong to the correct prime-order subgroup, preventing information leakage during ECDH key exchanges and signature forgery in ECDSA operations. Apply this update across all systems using cryptography for elliptic curve operations, particularly those handling SECT curves.

sudo dnf update python3-cryptography

Defensia detects this vulnerability

How to check if you are affected

  1. Run `python3 -c "import cryptography; print(cryptography.__version__)"` to check the installed cryptography library version
  2. Verify if the system uses elliptic curve cryptography by searching application code: `grep -r "EllipticCurve\|load_der_public_key\|load_pem_public_key" /path/to/application`
  3. Check application logs for ECDH key exchanges or ECDSA signature operations that might have processed untrusted public keys
  4. After patching, re-run the version check to confirm cryptography is updated to 46.0.5 or newer

FAQ

What is CVE-2026-26007?

CVE-2026-26007 is a vulnerability in Python's cryptography library where elliptic curve public key functions fail to validate that key points belong to the correct subgroup, allowing attackers to use crafted weak keys to leak private key information or forge signatures.

Is CVE-2026-26007 being actively exploited?

No, CVE-2026-26007 is not listed in the CISA Known Exploited Vulnerabilities catalog and no public exploits are currently available, though the vulnerability requires proper defensive measures given its cryptographic nature.

What versions of Python are affected by CVE-2026-26007?

All versions of the cryptography library prior to 46.0.5 are affected. The vulnerability impacts any application using cryptography for elliptic curve operations, regardless of the Python version.

How do I check if my server is vulnerable to CVE-2026-26007?

Execute `python3 -m pip show cryptography | grep Version` and compare the version number against 46.0.5; versions below this threshold are vulnerable.

Does Defensia detect CVE-2026-26007?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the cryptography library is installed on a monitored server, CVE-2026-26007 will appear in your dashboard with remediation steps.

Related Python CVEs

CVE-2026-25632CVSS 10EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.
CVE-2026-34938CVSS 10PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.
CVE-2026-33054CVSS 10Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
CVE-2026-28505CVSS 10Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the str_eval() function in notification_handler.py implements a sandboxed eval() for notification text templates. The sandbox attempts to restrict callable names by inspecting code.co_names of the compiled code object. However, co_names only contains names from the outer code object. When a lambda expression is used, it creates a nested code object whose attribute accesses are stored in code.co_consts, NOT in code.co_names. The sandbox never inspects nested code objects. This issue has been patched in version 2.17.0.
CVE-2026-26030CVSS 9.9Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically within the `InMemoryVectorStore` filter functionality. The problem has been fixed in version `python-1.39.4`. Users should upgrade this version or higher. As a workaround, avoid using `InMemoryVectorStore` for production scenarios.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-26007. Free for 1 server.

Get started free