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NVD / CVE Program· CNA mitre

CVE-2024-28757: libexpat through 2.6.1 allows an XML Entity Expansion attack when there is isolated use of external parsers (created via XML_ExternalEntityP

Noroxi assessment

Priority: Monitor (action score 31/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2% (FIRST EPSS); higher than 80.8% 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. No special conditions are required; it is repeatable.
  • Fixed version: expat (AlmaLinux:8) 2.5.0-1.el8_10; expat-devel (AlmaLinux:8) 2.5.0-1.el8_10; expat (AlmaLinux:9) 2.5.0-1.el9_3.1.

Low priority for now. Upgrade to expat (AlmaLinux:8) 2.5.0-1.el8_10; expat-devel (AlmaLinux:8) 2.5.0-1.el8_10; expat (AlmaLinux:9) 2.5.0-1.el9_3.1 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

libexpat through 2.6.1 allows an XML Entity Expansion attack when there is isolated use of external parsers (created via XML_ExternalEntityParserCreate).

HighCVSS 7.5 · v3.1—Proof of concept Fix available
Published
Mar 10, 2024
Updated
Oct 15, 2026
EPSS
2.0% · 80th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.0%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.5
CNA · mitre
7.5
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
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2024-28757

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
libexpat projectlibexpat
fedoraprojectfedora
netappactive iq unified manager
netapponcommand workflow automation
netappontap
netappontap tools
netappwindows host utilities
netapph300s firmware
netapph300s
netapph500s firmware
netapph500s
netapph700s firmware

and 9 more

Affected versions

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

  • fedoraproject fedora38
  • fedoraproject fedora39
  • fedoraproject fedora40
  • libexpat project libexpatbefore 2.6.2
  • netapp active iq unified managerall versions
  • netapp h300s firmwareall versions
  • netapp h410c firmwareall versions
  • netapp h410s firmwareall versions
  • netapp h500s firmwareall versions
  • netapp h610c firmwareall versions
  • netapp h610s firmwareall versions
  • netapp h700s firmwareall versions
  • netapp oncommand workflow automationall versions
  • netapp ontap9
  • netapp ontap tools10
  • netapp windows host utilitiesall versions

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8expatbefore 2.5.0-1.el8_102.5.0-1.el8_10
AlmaLinux:8expat-develbefore 2.5.0-1.el8_102.5.0-1.el8_10
AlmaLinux:9expatbefore 2.5.0-1.el9_3.12.5.0-1.el9_3.1
AlmaLinux:9expat-develbefore 2.5.0-1.el9_3.12.5.0-1.el9_3.1
Alpine:v3.16expatbefore 2.6.2-r02.6.2-r0
Debian:12expatbefore 2.5.0-1+deb12u42.5.0-1+deb12u4
Debian:12libxmltokfrom 0—
Debian:13expatbefore 2.6.1-22.6.1-2
openSUSE:Leap Micro 5.3expatbefore 2.4.4-150400.3.17.12.4.4-150400.3.17.1
openSUSE:Tumbleweedexpatbefore 2.6.2-1.12.6.2-1.1
Red Hat:enterprise_linux:8::baseosexpatbefore 0:2.5.0-1.el8_100:2.5.0-1.el8_10
Red Hat:enterprise_linux:8::baseosexpat-debuginfobefore 0:2.5.0-1.el8_100:2.5.0-1.el8_10
Red Hat:enterprise_linux:8::baseosexpat-debugsourcebefore 0:2.5.0-1.el8_100:2.5.0-1.el8_10
Red Hat:enterprise_linux:8::baseosexpat-develbefore 0:2.5.0-1.el8_100:2.5.0-1.el8_10
Red Hat:enterprise_linux:9::appstreamexpat-debuginfobefore 0:2.5.0-2.el9_40:2.5.0-2.el9_4
Red Hat:enterprise_linux:9::appstreamexpat-debuginfobefore 0:2.5.0-1.el9_3.10:2.5.0-1.el9_3.1
Red Hat:enterprise_linux:9::appstreamexpat-debugsourcebefore 0:2.5.0-1.el9_3.10:2.5.0-1.el9_3.1
Red Hat:enterprise_linux:9::appstreamexpat-debugsourcebefore 0:2.5.0-2.el9_40:2.5.0-2.el9_4
Red Hat:enterprise_linux:9::appstreamexpat-develbefore 0:2.5.0-2.el9_40:2.5.0-2.el9_4
Red Hat:enterprise_linux:9::appstreamexpat-develbefore 0:2.5.0-1.el9_3.10:2.5.0-1.el9_3.1
Red Hat:enterprise_linux:9::baseosexpatbefore 0:2.5.0-2.el9_40:2.5.0-2.el9_4
Red Hat:enterprise_linux:9::baseosexpatbefore 0:2.5.0-1.el9_3.10:2.5.0-1.el9_3.1
Red Hat:rhel_eus:9.2::appstreamexpat-debuginfobefore 0:2.5.0-1.el9_2.10:2.5.0-1.el9_2.1
Red Hat:rhel_eus:9.2::appstreamexpat-debugsourcebefore 0:2.5.0-1.el9_2.10:2.5.0-1.el9_2.1

+6

Same product

libexpat project: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-25236xmlparse.c in Expat (aka libexpat) before 2.4.5 allows attackers to insert namespace-separator characters into namespace URIs.
    50Plan
  • CVE-2022-23852Expat (aka libexpat) before 2.4.4 has a signed integer overflow in XML_GetBuffer, for configurations with a nonzero XML_CONTEXT_BYTES.
    41Plan
  • CVE-2022-22822addBinding in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow.
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2023-52425Feb 4, 2024 · libexpat through 2.5.0 allows a denial of service (resource consumption) because many full reparsings are required in the case of a large to
    31Monitor
  • ← EarlierCVE-2023-52426Feb 4, 2024 · libexpat through 2.5.0 allows recursive XML Entity Expansion if XML_DTD is undefined at compile time.
    22Monitor
  • Later →CVE-2024-45490Aug 29, 2024 · An issue was discovered in libexpat before 2.6.3.
    31Monitor

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:expat2.5.0-1.el9_3.1 · AlmaLinux:9Package registry (OSV)
almalinux:expat-devel2.5.0-1.el9_3.1 · AlmaLinux:9Package registry (OSV)
alpine:expat2.6.2-r0 · Alpine:v3.16Package registry (OSV)
debian:expat2.5.0-1+deb12u4 · Debian:12Package registry (OSV)
debian:expat2.6.1-2 · Debian:13Package registry (OSV)
opensuse:expat2.4.4-150400.3.17.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
red hat:expat0:2.5.0-2.el9_4 · Red Hat:enterprise_linux:9::baseosPackage registry (OSV)
red hat:expat-debuginfo0:2.5.0-2.el9_4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:expat-debugsource0:2.5.0-2.el9_4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:expat-devel0:2.5.0-2.el9_4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
suse:expat2.4.4-150400.3.17.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02024-05-03
Proof-of-concept repository on GitHubstars:02024-05-03

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.

  1. Published
  2. First PoC+54 d
  3. TodayNov 2, 2026+967 d

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.

  • CVE-2023-5242635 days apartlibexpat through 2.5.0 allows recursive XML Entity Expansion if XML_DTD is undefined at compile time.
    22Monitor

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.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-776 · Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')

CVSS vector

CVSS:3.1/AV:N/AC:L/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 (10 more)

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

All records