PatchTheCVECVE-2022-23990: Expat (aka libexpat) before 2.4.4 has an integer overflow in the doProlog function.
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HIGH 7.5REMOTEWATCHLISTUPGRADEUPGRADEDOWNGRADE
CVE-2022-23990 is a high-severity flaw (CVSS 7.5) affecting libexpat, nessus, communications metasolv solution. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Expat (aka libexpat) before 2.4.4 has an integer overflow in the doProlog function.
Why this priority
- High severity
- EPSS top 8%: very likely to be exploited
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 4.7% (top 8%) |
| CISA exploited list | No |
| Weakness | CWE-190 |
| Published | 2022-01-26 |
| Last modified | 2026-10-14 |
Publisher (CNA): MITRE · Vendor: debian · fedoraproject · libexpat project · oracle · siemens · tenable
Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
libexpat project libexpat UPGRADE
Affected: < 2.4.4
Fixed in: 2.4.4
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy libexpat || rpm -q libexpat || libexpat --version
2. UPGRADE to 2.4.4 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade libexpat
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade libexpat
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
tenable nessus UPGRADE
Affected: < 8.15.3 · >= 10.0.0 and < 10.1.1
Fixed in: 8.15.3, 10.1.1
Safe to downgrade to: a release before 10.0.0
1. Check installed version
apt-cache policy nessus || rpm -q nessus || nessus --version
2. UPGRADE to 8.15.3 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade nessus
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade nessus
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 10.0.0 (Debian / Ubuntu)
apt-cache madison nessus
sudo apt install nessus=<VERSION_BEFORE_10.0.0>
sudo apt-mark hold nessus
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list nessus
sudo dnf downgrade nessus-<VERSION_BEFORE_10.0.0>
sudo dnf versionlock add nessus
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
oracle communications metasolv solution DOWNGRADE
Affected: 6.3.1
Fixed in: no fixed release known
Safe to downgrade to: a release before 6.3.1
1. Check installed version
apt-cache policy communications-metasolv-solution || rpm -q communications-metasolv-solution || communications-metasolv-solution --version
2. No fixed release: DOWNGRADE to a release before 6.3.1 (Debian / Ubuntu)
apt-cache madison communications-metasolv-solution
sudo apt install communications-metasolv-solution=<VERSION_BEFORE_6.3.1>
sudo apt-mark hold communications-metasolv-solution
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list communications-metasolv-solution
sudo dnf downgrade communications-metasolv-solution-<VERSION_BEFORE_6.3.1>
sudo dnf versionlock add communications-metasolv-solution
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
debian debian linux MITIGATE
Affected: 10.0 · 11.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 10.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
fedoraproject fedora MITIGATE
Affected: 34 · 35
Fixed in: no fixed release known
Safe to downgrade to: a release before 34
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
siemens sinema remote connect server UPGRADE
Affected: < 3.1
Fixed in: 3.1
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy sinema-remote-connect-server || rpm -q sinema-remote-connect-server || sinema-remote-connect-server --version
2. UPGRADE to 3.1 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade sinema-remote-connect-server
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade sinema-remote-connect-server
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2022-23990?
libexpat: upgrade to 2.4.4; nessus: upgrade to 8.15.3, 10.1.1; communications metasolv solution: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2022-23990 being exploited?
CVE-2022-23990 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2022-23990 affect?
CVE-2022-23990 affects libexpat, nessus, communications metasolv solution. Severity is high (CVSS 7.5). Expat (aka libexpat) before 2.4.4 has an integer overflow in the doProlog function.
How urgent is CVE-2022-23990?
Priority 59/100. High severity; EPSS top 8%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist
Software pages
Debian vulnerabilities · Siemens vulnerabilities
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