CVE-2022-43680: In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEntityParserCreate in ou
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: 3.1% (FIRST EPSS); higher than 88% 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.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: expat (AlmaLinux:8) 2.2.5-10.el8_7.1; expat-devel (AlmaLinux:8) 2.2.5-10.el8_7.1; expat (AlmaLinux:9) 2.4.9-1.el9_1.1.
Low priority for now. Upgrade to expat (AlmaLinux:8) 2.2.5-10.el8_7.1; expat-devel (AlmaLinux:8) 2.2.5-10.el8_7.1; expat (AlmaLinux:9) 2.4.9-1.el9_1.1 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
In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEntityParserCreate in out-of-memory situations.
- BDU:2023-02688
- ALSA-2023:0103
- ALSA-2023:0337
- DLA-3165-1
- DSA-5266-1
- openSUSE-SU-2024:12449-1
- RHSA-2022:8548
- RHSA-2022:8549
- RHSA-2022:8550
- RHSA-2022:8553
- RHSA-2022:8554
- RHSA-2023:0103
- RHSA-2023:0337
- RHSA-2024:0421
- RHSA-2025:22785
- RHSA-2025:22871
- RLSA-2023:0103
- RLSA-2023:0337
- SUSE-SU-2022:3874-1
- SUSE-SU-2022:3884-1
- Published
- Oct 24, 2022
- Updated
- Oct 14, 2026
- EPSS
- 3.1% · 88th percentile
- CWE
- CWE-416
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- 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.
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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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| libexpat project | libexpat | cpe:2.3:a:libexpat_project:libexpat |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| netapp | h300s firmware | cpe:2.3:o:netapp:h300s_firmware |
| netapp | h300s | cpe:2.3:h:netapp:h300s |
| netapp | h500s firmware | cpe:2.3:o:netapp:h500s_firmware |
| netapp | h500s | cpe:2.3:h:netapp:h500s |
| netapp | h700s firmware | cpe:2.3:o:netapp:h700s_firmware |
| netapp | h700s | cpe:2.3:h:netapp:h700s |
| netapp | h410s firmware | cpe:2.3:o:netapp:h410s_firmware |
| netapp | h410s | cpe:2.3:h:netapp:h410s |
| netapp | h410c firmware | cpe:2.3:o:netapp:h410c_firmware |
and 6 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux11.0
- fedoraproject fedora35
- fedoraproject fedora36
- fedoraproject fedora37
- libexpat project libexpatup to 2.4.9 inclusive
- netapp active iq unified managerall versions
- netapp h300s firmwareall versions
- netapp h410c firmwareall versions
- netapp h410s firmwareall versions
- netapp h500s firmwareall versions
- netapp h700s firmwareall versions
- netapp hci compute node firmwareall versions
- netapp oncommand workflow automationall versions
- netapp solidfire & hci management nodeall versions
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | expat | before 2.2.5-10.el8_7.1 | 2.2.5-10.el8_7.1 |
| AlmaLinux:8 | expat-devel | before 2.2.5-10.el8_7.1 | 2.2.5-10.el8_7.1 |
| AlmaLinux:9 | expat | before 2.4.9-1.el9_1.1 | 2.4.9-1.el9_1.1 |
| AlmaLinux:9 | expat-devel | before 2.4.9-1.el9_1.1 | 2.4.9-1.el9_1.1 |
| Alpine:v3.13 | expat | before 2.2.10-r8 | 2.2.10-r8 |
| Alpine:v3.14 | expat | before 2.5.0-r0 | 2.5.0-r0 |
| Debian:10 | expat | before 2.2.6-2+deb10u6 | 2.2.6-2+deb10u6 |
| Debian:11 | expat | before 2.2.10-2+deb11u5 | 2.2.10-2+deb11u5 |
| Debian:12 | expat | before 2.5.0-1 | 2.5.0-1 |
| Debian:12 | libxmltok | from 0 | — |
| openSUSE:Leap 15.4 | expat | before 2.4.4-150400.3.12.1 | 2.4.4-150400.3.12.1 |
| openSUSE:Leap Micro 5.2 | expat | before 2.2.5-150000.3.25.1 | 2.2.5-150000.3.25.1 |
| openSUSE:Tumbleweed | expat | before 2.5.0-1.1 | 2.5.0-1.1 |
| Red Hat:enterprise_linux:8::appstream | firefox | before 0:102.5.0-1.el8_7 | 0:102.5.0-1.el8_7 |
| Red Hat:enterprise_linux:8::appstream | firefox-debuginfo | before 0:102.5.0-1.el8_7 | 0:102.5.0-1.el8_7 |
| Red Hat:enterprise_linux:8::appstream | firefox-debugsource | before 0:102.5.0-1.el8_7 | 0:102.5.0-1.el8_7 |
| Red Hat:enterprise_linux:8::baseos | expat | before 0:2.2.5-10.el8_7.1 | 0:2.2.5-10.el8_7.1 |
| Red Hat:enterprise_linux:8::baseos | expat-debuginfo | before 0:2.2.5-10.el8_7.1 | 0:2.2.5-10.el8_7.1 |
| Red Hat:enterprise_linux:8::baseos | expat-debugsource | before 0:2.2.5-10.el8_7.1 | 0:2.2.5-10.el8_7.1 |
| Red Hat:enterprise_linux:8::baseos | expat-devel | before 0:2.2.5-10.el8_7.1 | 0:2.2.5-10.el8_7.1 |
| Red Hat:enterprise_linux:9::appstream | expat-debuginfo | before 0:2.4.9-1.el9_1.1 | 0:2.4.9-1.el9_1.1 |
| Red Hat:enterprise_linux:9::appstream | expat-debugsource | before 0:2.4.9-1.el9_1.1 | 0:2.4.9-1.el9_1.1 |
| Red Hat:enterprise_linux:9::appstream | expat-devel | before 0:2.4.9-1.el9_1.1 | 0:2.4.9-1.el9_1.1 |
| Red Hat:enterprise_linux:9::baseos | expat | before 0:2.4.9-1.el9_1.1 | 0:2.4.9-1.el9_1.1 |
+26
Same product
libexpat project: all recordsOther 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-2022-25315Feb 18, 2022 · In Expat (aka libexpat) before 2.4.5, there is an integer overflow in storeRawNames.40Plan
- ← EarlierCVE-2022-40674Sep 14, 2022 · libexpat before 2.4.9 has a use-after-free in the doContent function in xmlparse.c.33Monitor
- Later →CVE-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 to31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:expat | 2.2.5-10.el8_7.1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:expat-devel | 2.2.5-10.el8_7.1 · AlmaLinux:8 | Package registry (OSV) |
| alpine:expat | 2.2.10-r8 · Alpine:v3.13 | Package registry (OSV) |
| debian:expat | 2.5.0-1 · Debian:12 | Package registry (OSV) |
| opensuse:expat | 2.4.4-150400.3.12.1 · openSUSE:Leap 15.4 | Package registry (OSV) |
| red hat:expat | 0:2.2.5-10.el8_7.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:expat-debuginfo | 0:2.2.5-10.el8_7.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:expat-debugsource | 0:2.2.5-10.el8_7.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:expat-devel | 0:2.2.5-10.el8_7.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:firefox | 0:102.5.0-1.el8_6 · Red Hat:rhel_eus:8.6::appstream | Package registry (OSV) |
| red hat:firefox-debuginfo | 0:102.5.0-1.el8_6 · Red Hat:rhel_eus:8.6::appstream | Package registry (OSV) |
| red hat:firefox-debugsource | 0:102.5.0-1.el8_6 · Red Hat:rhel_eus:8.6::appstream | Package registry (OSV) |
| rocky linux:expat | 0:2.2.5-10.el8_7.1 · Rocky Linux:8 | Package registry (OSV) |
| suse:expat | 2.1.0-21.28.1 · SUSE:OpenStack Cloud 9 | Package registry (OSV) |
| suse:expat | 2.4.4-150400.3.12.1 · SUSE:Linux Enterprise Micro 5.3 | Package 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.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:0 | 2022-12-15 |
| Proof-of-concept repository on GitHub | stars:0 | 2022-12-19 |
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.
- Published
- First PoC+51 d
- TodayOct 31, 2026+1468 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.
No commit or PR link among the references.
Credits
All researchersFinders, 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.
- 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-416 · Use After FreeCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Root cause
After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.
The bug in code
The whole CWE-416 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
free(dev->buf);
/* ... another thread is still running ... */
process(dev->buf);Fixed
lock(&dev->lock);
free(dev->buf);
dev->buf = NULL;
unlock(&dev->lock);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (13 more)Show less
- www.openwall.com/lists/oss-security/2024/01/03/5
- lists.debian.org/debian-lts-announce/2022/10/msg00033.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AJ5VY2VYXE4WTRGQ6LMGLF6FV3SY37YE/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BY4OPSIB33ETNUXZY2UPZ4NGQ3OKDY4D/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DPQVIF6TOJNY2T3ZZETFKR4G34FFREBQ/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FFCOMBSOJKLIKCGCJWHLJXO4EVYBG7AR/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUJ2BULJTZ2BMSKQHB6US674P55UCWWS/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XG5XOOB7CD55CEE6OJYKSACSIMQ4RWQ6/
- security.gentoo.org/glsa/202210-38
- security.netapp.com/advisory/ntap-20221118-0007/
- www.debian.org/security/2022/dsa-5266
- cert-portal.siemens.com/productcert/html/ssa-398330.html
- cert-portal.siemens.com/productcert/html/ssa-892048.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.