Vulnerability record
CVE-2026-128242
The short answer
CVE-2026-128242 affects actix actix-http and is rated high (CVSS 8.7). It is not in CISA's KEV catalog; EPSS puts the chance of exploitation in the next 30 days at 0.96%.
What it is
actix-http before 3.20.1 and actix-web before 4.18.2 contain an unbounded decompression vulnerability in encoding::Decoder that lets remote attackers exhaust memory and CPU via compressed bodies. Attackers can send small highly compressed gzip, deflate, Brotli or zstd request bodies to Json, Form, Bytes or String extractors, or serve them to awc clients, causing denial of service.
Weakness: CWE-409.
Severity
8.7 high
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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:X
Exploited (CISA KEV)
Not listed
CISA lists confirmed exploitation only
EPSS, next 30 days
0.96%
Higher than 62% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Affected products
actix-http, actix-web. NVD's record lists the exact affected versions.
References
- github.com/actix/actix-web
- github.com/actix/actix-web/blob/actix-http-v3.20.0/actix-http/src/encoding/decoder.rs#L239-L301
- github.com/actix/actix-web/commit/0d0be61bd757027bfcecbc53df1b7a600f21ecd0
- github.com/actix/actix-web/commit/41b54d23ea04f66758c15de7e4ab18325cd25280
- github.com/actix/actix-web/releases/tag/actix-http-v3.20.1
- github.com/actix/actix-web/releases/tag/actix-web-v4.18.2
- github.com/actix/actix-web/security/advisories/GHSA-qph8-7859-gq2f
- rustsec.org/advisories/RUSTSEC-2026-0448.html
- www.vulncheck.com/advisories/actix-http-before-3.20.1-and-actix-web-before-4.18.2-decompression-bomb-dos-via-encoding-decoder
Questions
Is CVE-2026-128242 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog as of 2026-11-13. FIRST's EPSS estimates a 0.96% chance of exploitation in the next 30 days.
How do I fix CVE-2026-128242?
Follow the vendor advisory in the references below. NVD lists the affected versions under its configurations.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Received. The description is NVD's text, quoted as published.
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