Cloudanix VulnDB

CVE-2026-33936

Medium · 5.3

CVSS

5.3

EPSS

0.5%

Published

Mar 27, 2026

CISA due date

—

The record

The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.

Affected packages

Ecosystem Package Introduced Fixed
SUSE:Linux Enterprise Module for Python 3 15 SP7 python-ecdsa 0 0.18.0-150400.12.6.1
openSUSE:Leap 15.6 python-ecdsa 0 0.18.0-150400.12.6.1
openSUSE:Leap 16.0 python-ecdsa 0 0.19.1-160000.4.1
openSUSE:Tumbleweed python-ecdsa 0 0.19.2-1.1

Related vulnerabilities