CVE-2018-19052: An issue was discovered in mod_alias_physical_handler in mod_alias.c in lighttpd before 1.4.50

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HIGH 7.5REMOTEWATCHLISTUPGRADEDOWNGRADEMITIGATE

CVE-2018-19052 is a high-severity flaw (CVSS 7.5) affecting lighttpd, backports sle, leap. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in mod_alias_physical_handler in mod_alias.c in lighttpd before 1.4.50. There is potential ../ path traversal of a single directory above an alias target, with a specific mod_alias configuration where the matched alias lacks a trailing '/' character, but the alias target filesystem path does have a trailing '/' character.

Why this priority

High severity
EPSS top 4%: 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	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	13.7% (top 4%)
CISA exploited list	No
Weakness	CWE-22
Published	2018-11-07
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · lighttpd · opensuse · suse

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

Am I affected?

Timeline

2018-11-07 05:29 UTCPublished CVE record published
2026-06-17 01:48 UTCUpdated Record last modified

lighttpd lighttpd UPGRADE

Affected: < 1.4.50

Fixed in: 1.4.50

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.4.50 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade lighttpd

Note

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

opensuse backports sle DOWNGRADE

Affected: 15.0 · 15.0 sp1

Fixed in: no fixed release known

Safe to downgrade to: a release before 15.0

1. Check installed version

apt-cache policy backports-sle || rpm -q backports-sle || backports-sle --version

2. No fixed release: DOWNGRADE to a release before 15.0 (Debian / Ubuntu)

apt-cache madison backports-sle sudo apt install backports-sle=<VERSION_BEFORE_15.0> sudo apt-mark hold backports-sle

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

dnf --showduplicates list backports-sle sudo dnf downgrade backports-sle-<VERSION_BEFORE_15.0> sudo dnf versionlock add backports-sle

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.

opensuse leap MITIGATE

Affected: 15.0 · 15.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 15.0

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.

suse suse linux enterprise server MITIGATE

Affected: 11 sp3 · 11 sp4 · 12 · 12 sp1 · 12 sp2 · 12 sp3 · 12 sp4

Fixed in: no fixed release known

Safe to downgrade to: a release before 11

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.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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.

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-2018-19052?

lighttpd: upgrade to 1.4.50; backports sle: downgrade or apply the listed mitigation; leap: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-19052 being exploited?

CVE-2018-19052 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-2018-19052 affect?

CVE-2018-19052 affects lighttpd, backports sle, leap. Severity is high (CVSS 7.5). An issue was discovered in mod_alias_physical_handler in mod_alias.c in lighttpd before 1.4.50. There is potential ../ path traversal of a single directory above an alias target, with a specific mod_alias configuration where the matched ali

How urgent is CVE-2018-19052?

Priority 65/100. High severity; EPSS top 4%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities · lighttpd vulnerabilities

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References

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