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NVD / CVE Program· CNA EEF

CVE-2026-23941: Request smuggling via first-wins Content-Length parsing in inets httpd

HighCVSS 7.0 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.51% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Erlang OTP 26.2.5.18, 27.3.4.9, 28.4.1; azl3 erlang 26.2.5.17-1 on Azure Linux 3.0 26.2.5.18-1; cbl2 erlang 25.3.2.21-4 on CBL Mariner 2.0 25.3.2.21-5.

Low priority for now. Upgrade to Erlang OTP 26.2.5.18, 27.3.4.9, 28.4.1; azl3 erlang 26.2.5.17-1 on Azure Linux 3.0 26.2.5.18-1; cbl2 erlang 25.3.2.21-4 on CBL Mariner 2.0 25.3.2.21-5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in Erlang OTP (inets httpd module) allows HTTP Request Smuggling. This vulnerability is associated with program files lib/inets/src/http_server/httpd_request.erl and program routines httpd_request:parse_headers/7. The server does not reject or normalize duplicate Content-Length headers. The earliest Content-Length in the request is used for body parsing while common reverse proxies (nginx, Apache httpd, Envoy) honor the last Content-Length value. This violates RFC 9112 Section 6.3 and allows front-end/back-end desynchronization, leaving attacker-controlled bytes queued as the start of the next request. This issue affects OTP from OTP 17.0 before OTP 26.2.5.18, OTP 27.3.4.9, and OTP 28.4.1, corresponding to inets from 5.10 before 9.1.0.5, 9.3.2.3, and 9.6.1. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

Published
Mar 13, 2026
Updated
Nov 11, 2026
EPSS
0.5% · 44th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
7.0
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Follow CVE-2026-23941

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
erlangerlang/inets
erlangerlang/otp

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

  • Erlang OTP

    • 17.0 and lateraffected · otpfixed in 26.2.5.18, 27.3.4.9, 28.4.1
    • 5.10 and lateraffected · otpfixed in 9.1.0.5, 9.3.2.3, 9.6.1
    • 84adefa331c4159d432d22840663c38f155cd4c1 and lateraffected · gitfixed in e775a332f623851385ab6ddb866d9b150612ddf6, a761d391d8d08316cbd7d4a86733ba932b73c45b, a4b46336fd25aa100ac602eb9a627aaead7eda18
    • e775a332f623851385ab6ddb866d9b150612ddf6 and laternot affected · git
    • a761d391d8d08316cbd7d4a86733ba932b73c45b and laternot affected · git
    • a4b46336fd25aa100ac602eb9a627aaead7eda18 and laternot affected · git
Affected versions · NVD (6)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • erlang erlang/inets5.10 and later · before 9.1.0.5
  • erlang erlang/inets9.3 and later · before 9.3.2.3
  • erlang erlang/inets9.6 and later · before 9.6.1
  • erlang erlang/otp17.0 and later · before 26.2.5.18
  • erlang erlang/otp27.0 and later · before 27.3.4.9
  • erlang erlang/otp28.0 and later · before 28.4.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12erlangbefore 1:25.2.3+dfsg-1+deb12u41:25.2.3+dfsg-1+deb12u4
Debian:13erlangbefore 1:27.3.4.1+dfsg-1+deb13u21:27.3.4.1+dfsg-1+deb13u2
Debian:14erlangbefore 1:27.3.4.9+dfsg-11:27.3.4.9+dfsg-1
openSUSE:Leap 16.0erlangbefore 27.1.3-160000.4.127.1.3-160000.4.1
openSUSE:Tumbleweederlang27before 27.1.3-2.127.1.3-2.1

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-28808ScriptAlias CGI targets bypass directory auth in inets httpd (mod_auth vs mod_cgi path mismatch)
    33Monitor
  • CVE-2026-48856httpc leaks Authorization header to cross-origin redirect targets
    28Monitor
  • CVE-2026-48858ftp client PASV response IP not validated against control peer, enabling SSRF and FTP bounce attacks
    25Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Erlang OTP26.2.5.18Vendor (CNA)
Erlang OTP27.3.4.9Vendor (CNA)
Erlang OTP28.4.1Vendor (CNA)
Erlang OTP9.1.0.5Vendor (CNA)
Erlang OTP9.3.2.3Vendor (CNA)
Erlang OTP9.6.1Vendor (CNA)
Erlang OTPa4b46336fd25aa100ac602eb9a627aaead7eda18Vendor (CNA)
Erlang OTPa761d391d8d08316cbd7d4a86733ba932b73c45bVendor (CNA)
Erlang OTPe775a332f623851385ab6ddb866d9b150612ddf6Vendor (CNA)
azl3 erlang 26.2.5.17-1 on Azure Linux 3.026.2.5.18-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 erlang 25.3.2.21-4 on CBL Mariner 2.025.3.2.21-5 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:erlang1:25.2.3+dfsg-1+deb12u4 · Debian:12Package registry (OSV)
opensuse:erlang27.1.3-160000.4.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:erlang2727.1.3-2.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Not on record for this CVE: EPSS history · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records