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NVD / CVE Program· CNA mitre

CVE-2023-27371: GNU libmicrohttpd before 0.9.76 allows remote DoS (Denial of Service) due to improper parsing of a multipart/form-data boundary in the…

Noroxi assessment

Priority: Monitor (action score 23/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.2% (FIRST EPSS); higher than 69.6% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: libmicrohttpd (AlmaLinux:8) 1:0.9.59-3.el8; libmicrohttpd-devel (AlmaLinux:8) 1:0.9.59-3.el8; libmicrohttpd-doc (AlmaLinux:8) 1:0.9.59-3.el8.

Low priority for now. Upgrade to libmicrohttpd (AlmaLinux:8) 1:0.9.59-3.el8; libmicrohttpd-devel (AlmaLinux:8) 1:0.9.59-3.el8; libmicrohttpd-doc (AlmaLinux:8) 1:0.9.59-3.el8 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

GNU libmicrohttpd before 0.9.76 allows remote DoS (Denial of Service) due to improper parsing of a multipart/form-data boundary in the postprocessor.c MHD_create_post_processor() method. This allows an attacker to remotely send a malicious HTTP POST packet that includes one or more '\0' bytes in a multipart/form-data boundary field, which - assuming a specific heap layout - will result in an out-of-bounds read and a crash in the find_boundary() function.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
Feb 28, 2023
Updated
Oct 14, 2026
EPSS
1.2% · 69th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.9
CNA · mitre
5.9
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
gnulibmicrohttpd

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • gnu libmicrohttpdbefore 0.9.76

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8libmicrohttpdbefore 1:0.9.59-3.el81:0.9.59-3.el8
AlmaLinux:8libmicrohttpd-develbefore 1:0.9.59-3.el81:0.9.59-3.el8
AlmaLinux:8libmicrohttpd-docbefore 1:0.9.59-3.el81:0.9.59-3.el8
AlmaLinux:9libmicrohttpdbefore 1:0.9.72-5.el91:0.9.72-5.el9
AlmaLinux:9libmicrohttpd-develbefore 1:0.9.72-5.el91:0.9.72-5.el9
AlmaLinux:9libmicrohttpd-docbefore 1:0.9.72-5.el91:0.9.72-5.el9
Debian:10libmicrohttpdbefore 0.9.62-1+deb10u10.9.62-1+deb10u1
Debian:12libmicrohttpdbefore 0.9.75-60.9.75-6
openSUSE:Leap Micro 5.3libmicrohttpdbefore 0.9.57-150000.3.3.10.9.57-150000.3.3.1
Red Hat:enterprise_linux:8::baseoslibmicrohttpdbefore 1:0.9.59-3.el81:0.9.59-3.el8
Red Hat:enterprise_linux:8::baseoslibmicrohttpd-debuginfobefore 1:0.9.59-3.el81:0.9.59-3.el8
Red Hat:enterprise_linux:8::baseoslibmicrohttpd-debugsourcebefore 1:0.9.59-3.el81:0.9.59-3.el8
Red Hat:enterprise_linux:8::crblibmicrohttpd-develbefore 1:0.9.59-3.el81:0.9.59-3.el8
Red Hat:enterprise_linux:8::crblibmicrohttpd-docbefore 1:0.9.59-3.el81:0.9.59-3.el8
Red Hat:enterprise_linux:9::appstreamlibmicrohttpdbefore 1:0.9.72-5.el91:0.9.72-5.el9
Red Hat:enterprise_linux:9::appstreamlibmicrohttpd-debuginfobefore 1:0.9.72-5.el91:0.9.72-5.el9
Red Hat:enterprise_linux:9::appstreamlibmicrohttpd-debugsourcebefore 1:0.9.72-5.el91:0.9.72-5.el9
Red Hat:enterprise_linux:9::crblibmicrohttpd-develbefore 1:0.9.72-5.el91:0.9.72-5.el9
Red Hat:enterprise_linux:9::crblibmicrohttpd-docbefore 1:0.9.72-5.el91:0.9.72-5.el9
Red Hat:rhel_eus:8.6::baseoslibmicrohttpdbefore 1:0.9.59-2.el8_6.11:0.9.59-2.el8_6.1
Red Hat:rhel_eus:8.6::baseoslibmicrohttpd-debuginfobefore 1:0.9.59-2.el8_6.11:0.9.59-2.el8_6.1
Red Hat:rhel_eus:8.6::baseoslibmicrohttpd-debugsourcebefore 1:0.9.59-2.el8_6.11:0.9.59-2.el8_6.1
Red Hat:rhel_eus:8.6::crblibmicrohttpd-develbefore 1:0.9.59-2.el8_6.11:0.9.59-2.el8_6.1
Red Hat:rhel_eus:8.6::crblibmicrohttpd-docbefore 1:0.9.59-2.el8_6.11:0.9.59-2.el8_6.1

+9

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-3466A flaw was found in libmicrohttpd.
    42Plan
  • CVE-2025-62689NULL pointer dereference vulnerability exists in GNU libmicrohttpd v1.0.2 and earlier.
    34Monitor
  • CVE-2025-59777NULL pointer dereference vulnerability exists in GNU libmicrohttpd v1.0.2 and earlier.
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2013-7038Dec 13, 2013 · The MHD_http_unescape function in libmicrohttpd before 0.9.32 might allow remote attackers to obtain sensitive information or cause a…
    26Monitor
  • ← EarlierCVE-2013-7039Dec 13, 2013 · Stack-based buffer overflow in the MHD_digest_auth_check function in libmicrohttpd before 0.9.32, when MHD_OPTION_CONNECTION_MEMORY_LIMIT…
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:libmicrohttpd1:0.9.72-5.el9 · AlmaLinux:9Package registry (OSV)
almalinux:libmicrohttpd-devel1:0.9.72-5.el9 · AlmaLinux:9Package registry (OSV)
almalinux:libmicrohttpd-doc1:0.9.72-5.el9 · AlmaLinux:9Package registry (OSV)
debian:libmicrohttpd0.9.75-6 · Debian:12Package registry (OSV)
opensuse:libmicrohttpd0.9.57-150000.3.3.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
red hat:libmicrohttpd1:0.9.72-5.el9 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:libmicrohttpd-debuginfo1:0.9.72-5.el9 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:libmicrohttpd-debugsource1:0.9.72-5.el9 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:libmicrohttpd-devel1:0.9.72-5.el9 · Red Hat:enterprise_linux:9::crbPackage registry (OSV)
red hat:libmicrohttpd-doc1:0.9.72-5.el9 · Red Hat:enterprise_linux:9::crbPackage registry (OSV)
rocky linux:libmicrohttpd1:0.9.72-5.el9 · Rocky Linux:9Package registry (OSV)
suse:libmicrohttpd0.9.57-150000.3.3.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records