CVE-2026-62298: Null Dereference

Description

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.

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EPSS — Exploit Prediction

0.0050

Probability of exploitation

0.43%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-476 CWE-476

References

Other References

https://github.com/mouse07410/asn1c/commit/3f7d3bbac8cd195d552945e79586ca5000f33280 https://github.com/mouse07410/asn1c/commit/71ae41bd1cb146a432a39f72010b48f45ad69463 https://github.com/mouse07410/asn1c/releases/tag/v1.2.5 https://github.com/mouse07410/asn1c/security/advisories/GHSA-rcj5-gcvg-x796

Frequently Asked Questions

What is CVE-2026-62298? +

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.

How do I check if I'm vulnerable to CVE-2026-62298? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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