CVE-2026-77281: caddyserver caddy
CVSS: 6.9v4.0MediumDeferred
AliasesUBUNTU-CVE-2026-77281DEBIAN-CVE-2026-77281GHSA-j8px-rmrx-76h9CVE-2026-92284CVE-2026-92700GO-2026-6512UBUNTU-CVE-2026-92284UBUNTU-CVE-2026-92700
Published 17-09-2026Last modified 18-09-2026
Vulnerability summary
CVE-2026-77281 is a medium (CVSS 6.9) vulnerability in caddyserver caddy. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 40.9% of scored vulnerabilities.
CVSS score
6.9/10
010
Medium · v4.0 (NVD)EPSS score
0.49%
0%100%
Low · +0.13 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 17-09-2026PublishedVulnerability first disclosed.
- 18-09-2026Last modifiedVulnerability information updated.
Description
Caddy is an extensible server platform that uses TLS by default. In version 2.11.3 and earlier, in modules/caddyhttp/replacer.go, resolving http.request.body reads the complete request body with an unbounded io.Copy before request-body middleware limits apply, allowing memory exhaustion and process termination.
CVSS metrics
5 scores · 5 sources · 2 versionsMedium 6.9Preferred score · NVD (NIST)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSources2 sources · 6.3–6.9
- OSV · UbuntuEcosystem advisory · calculated6.3MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NDiffers
Medium 6.5Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:LSourcesAll 3 agree
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
- OSV · GoEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
EPSS trend
Probability
0.49%
Chance of exploitation in the next 30 days
Percentile
41%
Versus all other CVEs
30-day change
+0.13 pp
From 0.36% on 20-09-2026
20-09-202620-10-2026
EPSS score0.49%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
- CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
- CWE-178Improper Handling of Case SensitivityThe product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Affected systems
Caddyserver1 product
- caddy< 2.11.4
Debian1 product
- caddyAll versions (No fix recorded) | < 2.11.4-1
Github.com/caddyserver/caddy1 product
- v2< 2.11.4
Ubuntu1 product
- caddyAll versions (No fix recorded)
4 vendors · 4 products
References
13 links- github.com/caddyserver/caddy/security/advisories/GHSA-j8px-rmrx-76h9X Refsource CONFIRMREPORTWEBAdvisory
- github.com/caddyserver/caddy/commit/176b043b0104cee3f894023cd5a598ac29e404bbX Refsource MISCREPORTWEBFIX
- github.com/caddyserver/caddyPACKAGE