CVE-2020-23911Public exploit

Compiler crash via malformed diagnostic argument

Published Jul 18, 2023 · Updated Oct 28, 2024

NULL pointer dereference in asn1c 0.9.28 and earlier allows local users to crash the compiler with a crafted ASN.1 file. While fixing an ENUM definition, asn1f_fix_enum passes a malformed diagnostic argument to _default_error_logger, whose vfprintf path reads address 0x1 as a string. The user must run the semantic-fixing stage on the file; the demonstrated consequence is termination of that compiler process, not code execution or data disclosure.

CVSS severity5.5
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in asn1c 0.9.28 and earlier allows local users to crash the compiler with a crafted ASN.1 file. While fixing an ENUM definition, asn1f_fix_enum passes a malformed diagnostic argument to _default_error_logger, whose vfprintf path reads address 0x1 as a string. The user must run the semantic-fixing stage on the file; the demonstrated consequence is termination of that compiler process, not code execution or data disclosure.

The record

CVE
CVE-2020-23911
Published
Jul 18, 2023
Updated
Oct 28, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 18, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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