CVE-2026-45135: Caddy is an extensible server platform that uses TLS by default

Q: How do I fix CVE-2026-45135?

caddy: upgrade to 2.11.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-45135 being exploited?

CVE-2026-45135 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-2026-45135 affect?

CVE-2026-45135 affects caddy. Severity is high (CVSS 8.1). Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when t

Q: How urgent is CVE-2026-45135?

Priority 51/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 8.1REMOTEUPGRADE

CVE-2026-45135 is a high-severity flaw (CVSS 8.1) affecting caddy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when the request path contains a non-ASCII byte. Two distinct flaws in that fallback let an attacker mislead Caddy's FastCGI splitting into treating a non-.php (or other configured split_path extension) file as a scr

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-20, CWE-176, CWE-178
Published	2026-06-23
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: caddyserver

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-23 18:17 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

caddyserver caddy UPGRADE

Affected: >= 2.7.0 and < 2.11.3

Fixed in: 2.11.3

Safe to downgrade to: a release before 2.7.0

1. Check installed version

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

2. UPGRADE to 2.11.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade caddy

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 2.7.0 (Debian / Ubuntu)

apt-cache madison caddy sudo apt install caddy=<VERSION_BEFORE_2.7.0> sudo apt-mark hold caddy

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list caddy sudo dnf downgrade caddy-<VERSION_BEFORE_2.7.0> sudo dnf versionlock add caddy

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.

Exact fixes by distribution

Go · github.com/caddyserver/caddy/v2 · FIXED · 2.11.3 · vulnerable: >= 2.7.0, <= 2.10.2 · source

go get github.com/caddyserver/caddy/v2@v2.11.3 go list -m github.com/caddyserver/caddy/v2

Fedora 46 · rust-opendal-core · FIXED · 0.59.1-2.fc46 · FEDORA-2026-4607543819 · source

sudo dnf upgrade --advisory=FEDORA-2026-4607543819

Fedora ELN · velocitty · FIXED · 1.0.3-2.eln159 · FEDORA-2026-edae8cd295 · source

sudo dnf upgrade --advisory=FEDORA-2026-edae8cd295

Debian 12 · caddy · NOT AFFECTED

Debian 13 · caddy · NOT AFFECTED

Alpine 3.23 · caddy · FIXED · caddy-2.11.4-r0

apk add --upgrade caddy apk info -v caddy

Alpine 3.24 · caddy · FIXED · caddy-2.11.4-r0

apk add --upgrade caddy apk info -v caddy

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/caddyserver/caddy/security/advisories/GHSA-m675-2p33-xv9g

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-2026-45135?

caddy: upgrade to 2.11.3. Exact commands for each OS are on this page.

Is CVE-2026-45135 being exploited?

CVE-2026-45135 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-2026-45135 affect?

CVE-2026-45135 affects caddy. Severity is high (CVSS 8.1). Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when t

How urgent is CVE-2026-45135?

Priority 51/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities · Go (Golang) vulnerabilities · Caddy vulnerabilities

Related CVEs

CVE-2026-52844 HIGH 7.5 UPGRADE Caddy is an extensible server platform that uses TLS by default
CVE-2026-52845 HIGH 8.1 UPGRADE Caddy is an extensible server platform that uses TLS by default
CVE-2026-45692 MEDIUM 5.4 UPGRADE Caddy is an extensible server platform that uses TLS by default

References

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