CVE-2019-15890: libslirp 4.0.0, as used in QEMU 4.1.0, has a use-after-free in ip_reass in ip_input.c.

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HIGH 7.5REMOTEDOWNGRADEDOWNGRADE

CVE-2019-15890 is a high-severity flaw (CVSS 7.5) affecting libslirp, qemu. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libslirp 4.0.0, as used in QEMU 4.1.0, has a use-after-free in ip_reass in ip_input.c.

Why this priority

High severity
EPSS top 9%: very likely to be exploited
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	4.0% (top 9%)
CISA exploited list	No
Weakness	CWE-416
Published	2019-09-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: libslirp project · qemu

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-09-06 17:15 UTCPublished CVE record published
2026-06-17 02:21 UTCUpdated Record last modified

libslirp project libslirp DOWNGRADE

Affected: 4.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy libslirp || rpm -q libslirp || libslirp --version

2. No fixed release: DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison libslirp sudo apt install libslirp=<VERSION_BEFORE_4.0.0> sudo apt-mark hold libslirp

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list libslirp sudo dnf downgrade libslirp-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add libslirp

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.

qemu qemu DOWNGRADE

Affected: 4.1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1.0

1. Check installed version

apt-cache policy qemu || rpm -q qemu || qemu --version

2. No fixed release: DOWNGRADE to a release before 4.1.0 (Debian / Ubuntu)

apt-cache madison qemu sudo apt install qemu=<VERSION_BEFORE_4.1.0> sudo apt-mark hold qemu

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list qemu sudo dnf downgrade qemu-<VERSION_BEFORE_4.1.0> sudo dnf versionlock add qemu

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.

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.

Quick answers

How do I fix CVE-2019-15890?

libslirp: downgrade or apply the listed mitigation; qemu: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-15890 being exploited?

CVE-2019-15890 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-2019-15890 affect?

CVE-2019-15890 affects libslirp, qemu. Severity is high (CVSS 7.5). libslirp 4.0.0, as used in QEMU 4.1.0, has a use-after-free in ip_reass in ip_input.c.

How urgent is CVE-2019-15890?

Priority 54/100. High severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action

Software pages

QEMU vulnerabilities

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References

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