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Fencer Vulns
high 8.1

CVE-2026-75614 json

ASN1SCC: Out-of-bounds write in BitStream_DecodeConstraintWholeNumber (uPER/ACN)

published 2026-11-05 3 d ago modified 2026-11-05 3 d ago also EUVD-2026-117599

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

ASN1SCC is an open source ASN.1 compiler for embedded systems. Prior to 4.7.0.1, BitStream_DecodeConstraintWholeNumber in asn1crt/asn1crt_encoding.c reads enough bits for a constrained integer but does not reject values above the declared range when the encoded range is not a power of two. Generated uPER and ACN decoders for variable-size SEQUENCE OF, OCTET STRING, BIT STRING, and string values use the invalid result as a loop or copy length, so a crafted over-range size field can write beyond a destination buffer. Decoding untrusted affected data can corrupt heap or stack memory, cause a crash, or potentially permit code execution. This issue is fixed in version 4.7.0.1.

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
3 d ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/esa/asn1scc/security/advisories/GHSA-825c-7h77-2jjq referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • esa asn1scc

Classification

Weakness
  • CWE-129 Improper Validation of Array Index
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.