CVE-2026-59884 — pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without …
Published: 2026-07-14 · CVSS: 7.5 · CVSS 3.1
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7