CVE-2022-43680 — In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared...
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 2.5% (30-day exploitation probability)+13
- Technical severity (high)+6
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Fedoraproject Fedora, Libexpat Project Libexpat…).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Debian | Debian Linux | version 10.0version 11.0 | Vulnerable | NIST National Vulnerability Database |
| Fedoraproject | Fedora | version 35version 36version 37 | Vulnerable | NIST National Vulnerability Database |
| Libexpat Project | Libexpat | ≤ 2.4.9 | Vulnerable | NIST National Vulnerability Database |
| Netapp | Active Iq Unified Manager | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | H300s Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | H410c Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | H410s Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | H500s Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | H700s Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Hci Compute Node Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Oncommand Workflow Automation | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Solidfire & Hci Management Node | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.5 | CVSS 3.1 | High | 3.9 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
| 7.5 | CVSS 3.1 | High | 3.9 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 7.5 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.5 | CVSS 3.1 | High | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · libexpat project/libexpat, debian/debian linux, fedoraproject/fedora, netapp/h300s firmware, netapp/h500s firmware, neta
- CVSS changed · 7.5
- Source status changed · → Modified
- Record created in this database
- 2022
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
32 on the record
- github.com/libexpat/libexpat/pull/616
- github.com/libexpat/libexpat/pull/650
- github.com/libexpat/libexpat/issues/649
- lists.debian.org/debian-lts-announce/2022/10/msg00033.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FFCO
- nvd.nist.gov/vuln/detail/CVE-2022-43680
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BY4O
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IUJ2BU
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AJ5V
- security.netapp.com/advisory/ntap-20221118-0007/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AJ5V
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FFCO
- security.netapp.com/advisory/ntap-20221118-0007
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XG5XOO
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUJ2
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BY4OPS
- www.debian.org/security/2022/dsa-5266
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DPQVIF
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUJ2
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DPQV
- cert-portal.siemens.com/productcert/html/ssa-398330.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BY4O
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XG5X
- github.com/advisories/GHSA-4hjv-8mmr-jxwv
- www.openwall.com/lists/oss-security/2024/01/03/5
- security.gentoo.org/glsa/202210-38
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DPQV
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/AJ5VY2
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FFCOMB
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XG5X
- www.openwall.com/lists/oss-security/2023/12/28/5
- cert-portal.siemens.com/productcert/html/ssa-892048.html
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-76957 Use After Free in Libexpat Project Libexpat Aug 20, 2026
- High CVE-2026-76956 In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code… Aug 20, 2026
- High CVE-2026-66046 Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic… Aug 18, 2026
- High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
- Medium CVE-2026-14355 ext/openssl: Memory corruption in openssl_encrypt with AES-WRAP-PAD Jul 3, 2026
- Medium CVE-2026-56968 Use of Uninitialized Resource in Gnu Sasl Jun 23, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2022-43680 is "In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared...", rated High. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 2.46% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.