CVE-2023-27371Public exploitNetwork attack vector

Remote crash via multipart boundary length underflow

Published Feb 28, 2023 · Updated Mar 11, 2025

Out-of-bounds read in GNU libmicrohttpd before 0.9.76 allows remote attackers to crash HTTP servers via crafted multipart POST requests. MHD_create_post_processor() applies strlen() to a quoted boundary containing NUL bytes, then subtracts two from a one-byte unsigned length; find_boundary() passes the underflowed length to memcmp(). The optional MHD_PostProcessor must process the request, and successful service interruption depends on a favorable heap layout or nonstandard allocator.

CVSS severity5.9
Medium
EPSS probability1.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in GNU libmicrohttpd before 0.9.76 allows remote attackers to crash HTTP servers via crafted multipart POST requests. MHD_create_post_processor() applies strlen() to a quoted boundary containing NUL bytes, then subtracts two from a one-byte unsigned length; find_boundary() passes the underflowed length to memcmp(). The optional MHD_PostProcessor must process the request, and successful service interruption depends on a favorable heap layout or nonstandard allocator.

The record

CVE
CVE-2023-27371
Published
Feb 28, 2023
Updated
Mar 11, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 11, 2025Record 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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