CVE-2016-10195: The name_parse function in evdns.c in libevent before 2.1.6-beta allows remote attackers to have unspecified i

Q: How do I fix CVE-2016-10195?

libevent: upgrade to newer than 2.1.5; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2016-10195 being exploited?

CVE-2016-10195 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2016-10195 affect?

CVE-2016-10195 affects libevent, debian linux. Severity is critical (CVSS 9.8). The name_parse function in evdns.c in libevent before 2.1.6-beta allows remote attackers to have unspecified impact via vectors involving the label_len variable, which triggers an out-of-bounds stack read.

Q: How urgent is CVE-2016-10195?

Priority 73/100. Critical severity; EPSS top 6%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2016-10195 is a critical-severity flaw (CVSS 9.8) affecting libevent, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The name_parse function in evdns.c in libevent before 2.1.6-beta allows remote attackers to have unspecified impact via vectors involving the label_len variable, which triggers an out-of-bounds stack read.

Why this priority

Critical severity
EPSS top 6%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	6.7% (top 6%)
CISA exploited list	No
Weakness	CWE-125
Published	2017-03-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · libevent project

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

Am I affected?

Timeline

2017-03-15 15:59 UTCPublished CVE record published
2026-06-17 00:39 UTCUpdated Record last modified

libevent project libevent UPGRADE

Affected: <= 2.1.5

Fixed in: newer than 2.1.5

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 2.1.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libevent

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libevent

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · root · FIXED · 6.40.04-7.fc46 · FEDORA-2026-7329868400 · source

sudo dnf upgrade --advisory=FEDORA-2026-7329868400

Debian 12 · libevent · FIXED · 2.0.21-stable-3

sudo apt update && sudo apt install --only-upgrade libevent dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libevent)" ge "2.0.21-stable-3" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · libevent · FIXED · 2.0.21-stable-3

sudo apt update && sudo apt install --only-upgrade libevent dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libevent)" ge "2.0.21-stable-3" && echo PATCHED || echo STILL-VULNERABLE

RHEL 6 · firefox · FIXED · firefox-52.1.0-2.el6_9

sudo dnf upgrade --advisory=RHSA-2017:1104 rpm -q firefox

RHEL 6 · thunderbird · FIXED · thunderbird-52.1.0-1.el6_9

sudo dnf upgrade --advisory=RHSA-2017:1201 rpm -q thunderbird

RHEL 7 · firefox · FIXED · firefox-52.1.0-2.el7_3

sudo dnf upgrade --advisory=RHSA-2017:1106 rpm -q firefox

RHEL 7 · thunderbird · FIXED · thunderbird-52.1.0-1.el7_3

sudo dnf upgrade --advisory=RHSA-2017:1201 rpm -q thunderbird

RHEL 5 · firefox · DEFERRED

Alpine 3.20 · libevent · FIXED · libevent-2.1.8-r0

apk add --upgrade libevent apk info -v libevent

Alpine 3.21 · libevent · FIXED · libevent-2.1.8-r0

apk add --upgrade libevent apk info -v libevent

Alpine 3.22 · libevent · FIXED · libevent-2.1.8-r0

apk add --upgrade libevent apk info -v libevent

Alpine 3.23 · libevent · FIXED · libevent-2.1.8-r0

apk add --upgrade libevent apk info -v libevent

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-2016-10195?

libevent: upgrade to newer than 2.1.5; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-10195 being exploited?

CVE-2016-10195 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-2016-10195 affect?

CVE-2016-10195 affects libevent, debian linux. Severity is critical (CVSS 9.8). The name_parse function in evdns.c in libevent before 2.1.6-beta allows remote attackers to have unspecified impact via vectors involving the label_len variable, which triggers an out-of-bounds stack read.

How urgent is CVE-2016-10195?

Priority 73/100. Critical severity; EPSS top 6%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2016-10197 HIGH 7.5 MITIGATE UPGRADE The search_make_new function in evdns.c in libevent before 2.1.6-beta allows attackers to cause a denial of se
CVE-2016-10196 HIGH 7.5 MITIGATE UPGRADE Stack-based buffer overflow in the evutil_parse_sockaddr_port function in evutil.c in libevent before 2.1.6-be
CVE-2015-6525 HIGH 7.5 MITIGATE DOWNGRADE Multiple integer overflows in the evbuffer API in Libevent 2.0.x before 2.0.22 and 2.1.x before 2.1.5-beta all
CVE-2014-6272 HIGH 7.5 MITIGATE DOWNGRADE Multiple integer overflows in the evbuffer API in Libevent 1.4.x before 1.4.15, 2.0.x before 2.0.22, and 2.1.x

References

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