TI-2026-36664 Aliases CVE-2026-49753 GHSA-mjqx-c6f6-7rc2

HTTP response smuggling in Mint HTTP/1 client via lenient Content-Length parsing

MEDIUM 61CWE-444Published 2026-06-02 · Updated 2026-06-02

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: —
Confidentiality · integrity · availability: None · Low · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint Mint allows attacker-controlled HTTP/1 servers to desynchronise response framing on shared connections. Mint's HTTP/1 Content-Length parser, Mint.HTTP1.Parse.content_length_header/1 in lib/mint/http1/parse.ex, parses the header value with Integer.parse/1, which accepts an optional + or - sign prefix. The length >= 0 guard rejects negatives, but inputs such as +0 or +123 are returned as valid lengths. RFC 7230 specifies Content-Length = 1*DIGIT, with no sign character permitted. A fronting proxy or load balancer that strictly enforces the grammar will reject or reframe a header like Content-Length: +0, while Mint silently treats it as zero. When Mint reuses the socket (keep-alive, pipelining, or any pooled connection shared across requesters), the parser disagreement is a response-smuggling primitive: the proxy delimits the body one way, Mint another, and bytes from one response get attributed to the next. Where the same Mint connection is shared across trust boundaries, an attacker-controlled upstream can leak bytes into a different consumer's response stream. This issue affects mint: from 0.1.0 before 1.9.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00301 23rd percentileScored 2026-11-07

Fix Fixed mint (elixir-mint): 1.9.0mint (Hex): 1.9.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
elixir-mint	mint	0.1.0 to before 1.9.0	1.9.0	Patch available	CNA
—	mint (Hex)	before 1.9.0	1.9.0	Patch available	GHSA-mjqx-c6f6-7rc2

mint Vendorelixir-mint Affected 0.1.0 to before 1.9.0 Fixed in 1.9.0 Patch available CNA
mint (Hex) Vendor— Affected before 1.9.0 Fixed in 1.9.0 Patch available GHSA-mjqx-c6f6-7rc2

CPE names CNA · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:elixir-mint:mint::::::::	—	—	—

cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:* Versions — — ·—

Remediation

Fix · CNA mint (elixir-mint) Fixed in 1.9.0
Fix · GHSA-mjqx-c6f6-7rc2 mint (Hex) Fixed in 1.9.0 Advisory →

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-06-02
elixir-mint mint 1.9.0
4 records Highest priority Priority HIGH 2 HIGH, 2 MEDIUM
Other records, highest priority first
- TI-2026-36665 HTTP/2 CONTINUATION flood in Mint client via unbounded header-block accumulationPriority HIGH 75
- TI-2026-36126 Unbounded conn.streams growth in Mint HTTP/2 client via unenforced PUSH_PROMISE concurrencyPriority HIGH 75
- TI-2026-36125 CRLF injection in HTTP/1 request line via unvalidated method in MintPriority MEDIUM 44
Show all 4 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-49753
2026-10-03 Alias added: GHSA-mjqx-c6f6-7rc2

References

Patch 1

https://github.com/elixir-mint/mint/commit/47e48027480228e4e32a0b4df39db497b4804921

Advisory 2

Other 3

TI-2026-41929 Unauthenticated denial-of-service via unbounded HPACK integer decoding in hpax CVSS 4.0HIGH 8.7
TI-2026-40963 mint buffers an entire chunked response chunk in memory in Mint.HTTP1.decode_body/5 CVSS 4.0HIGH 8.7
TI-2026-36665 HTTP/2 CONTINUATION flood in Mint client via unbounded header-block accumulation CVSS 4.0HIGH 8.2
TI-2026-36126 Unbounded conn.streams growth in Mint HTTP/2 client via unenforced PUSH_PROMISE concurrency CVSS 4.0HIGH 8.2
TI-2026-57046 Unbounded HTTP/1 status-line and chunk-extension buffering in Mint causes memory-exhaustion DoS CVSS 4.0HIGH 8.2
TI-2026-41932 Unbounded HTTP/1 response-header and chunked-trailer accumulation in Mint causes memory-exhaustion DoS CVSS 4.0HIGH 8.2

See all 14 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences