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VulnerabilityPublished

CVE-2026-49756: wojtekmach req · CRLF Injection

Affects wojtekmach reqSource CVE Database V5

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Not known to be exploited · CVSS 2.1 Low : upgrade to 0.6.0 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
2.1Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.6.0, 74506ff2c5addf74df85d79dc726e9b2e264a8ba
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade req to 0.6.0; req to 74506ff2c5addf74df85d79dc726e9b2e264a8ba.

Affected software

ProductAffectedFixed in
wojtekmachreqAffected
  • >=0.5.3 <0.6.0
Fixed in
  • 0.6.0
wojtekmachreqAffected
  • ≥ 60253dbe9436cb8e9c738f895032f2e87939b597, < 74506ff2c5addf74df85d79dc726e9b2e264a8ba
Fixed in
  • 74506ff2c5addf74df85d79dc726e9b2e264a8ba
Hexreqpkg:hex/reqOther threatsAffected
  • >=0.5.3 <0.6.0
Fixed in
  • 0.6.0

CPE configurations (1)

  • cpe:2.3:a:wojtekmach:req:*:*:*:*:*:*:*:*

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, avoid forwarding user-controlled filenames, field names, or MIME types through Req.post/2 with form_multipart enabled. Consider sanitizing or validating these inputs to remove CR and LF characters before passing them to the req library.

Description

CVE-2026-49756 is a CRLF injection vulnerability in the wojtekmach req library versions 0.5.3 before 0.6.0. It occurs because Req.Utils.encode_form_part/2 directly interpolates user-supplied name, filename, and content_type values into multipart headers without escaping or stripping CRLF characters. This allows an attacker to inject arbitrary headers or smuggle additional multipart fields by including CR or LF characters in these values, especially when using %File.Stream{} where filenames may contain such characters. The vulnerability enables multipart parameter smuggling in downstream requests.

References

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