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Fencer Intel
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CVE-2026-62298 json

asn1c: ASAN crash with decode of open types

published 4mo ago modified 12d ago also EUVD-2026-114330 , GHSA-rcj5-gcvg-x796

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository mouse07410/asn1c. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
0.0
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

mouse07410/asn1c is an ASN.1 compiler. Prior to 1.2.5, `OPEN TYPE` decoding can dereference an unallocated member pointer and crash the consuming program. `OPEN_TYPE_aper_get` in `OPEN_TYPE_aper.c`, `OPEN_TYPE_ber_get` in `OPEN_TYPE_ber.c`, `OPEN_TYPE_oer_get` in `OPEN_TYPE_oer.c`, and `OPEN_TYPE_uper_get` in `OPEN_TYPE_uper.c` share the pattern: a conditional null check on `*memb_ptr2` resets presence only when the member exists, but execution then unconditionally computes an inner value from that pointer and a member offset. If the `OPEN TYPE` member has not been allocated, the null-pointer arithmetic and subsequent read cause a segmentation fault. The advisory demonstrates UPER and APER crashes for `E2connectionUpdateAcknowledge`, notes that `E2AP` uses APER, and provides a BER reproducer; OER is also explicitly identified as affected. This issue is fixed in version 1.2.5.

Patch / fix

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
12d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 0.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 0.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • mouse07410 asn1c

Classification

Weakness

References

Sources

Fencer Intel 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.

The maintainers of mouse07410/asn1c published their own advisory on GitHub. Reviewed sources take precedence over it.