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TI-2026-49185 Aliases CVE-2026-70399

httpd does not enforce the documented default max_clients connection limit

Priority MEDIUM 45CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-770.

Summary

Allocation of Resources Without Limits or Throttling vulnerability in Erlang/OTP inets httpd allows an unauthenticated remote attacker to cause denial of service by opening and holding open a large number of connections. The max_clients option is documented to default to 150, and the inets hardening guide presents that limit as the first layer of denial-of-service defence, but a server that does not set it explicitly accepts an unlimited number of simultaneous connections. Establishing the connections is sufficient; no valid request and no authentication are required. The accept gate in httpd_manager:handle_new_connection/4 reads the option with httpd_util:lookup/2, which returns undefined when the key is absent, rather than the three-argument form carrying the 150 default that the neighbouring get_ustate/2 uses. Erlang term ordering places every integer before every atom, so the Count =< Max guard holds for any connection count and the server never returns {reject, busy}. Each accepted connection occupies a worker process and a socket for as long as it is held, driving the node towards process, memory and file descriptor exhaustion. Servers that set max_clients explicitly are unaffected, because a configured value is applied as intended. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00927 60th percentileScored 2026-11-07
Fix Fixed OTP (Erlang): 27.3.4.17, 28.5.0.6, 29.0.6 +3Red Hat: 1 advisory

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
ErlangOTP17.0 to before 27.3.4.17; 28.0 to before 28.5.0.6; 29.0 to before 29.0.627.3.4.17, 28.5.0.6, 29.0.6Patch availableCNA
ErlangOTP5.10 to before 9.3.2.7; 9.4 to before 9.6.2.3; 9.7 to before 9.7.29.3.2.7, 9.6.2.3, 9.7.2Patch availableCNA
  • OTP VendorErlang Affected 17.0 to before 27.3.4.17; 28.0 to before 28.5.0.6; 29.0 to before 29.0.6 Fixed in 27.3.4.17, 28.5.0.6, 29.0.6 Patch available CNA
  • OTP VendorErlang Affected 5.10 to before 9.3.2.7; 9.4 to before 9.6.2.3; 9.7 to before 9.7.2 Fixed in 9.3.2.7, 9.6.2.3, 9.7.2 Patch available CNA

CPE names CNA · 1

CPEVersionsRoleVendor
cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*——Erlang
  • cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:* Versions — — ·Erlang

Remediation

  • Fix · CNA OTP (Erlang) Fixed in 27.3.4.17, 28.5.0.6, 29.0.6
  • Fix · CNA OTP (Erlang) Fixed in 9.3.2.7, 9.6.2.3, 9.7.2

Red Hat 1 advisory

  • RHSA-2026:62531 Released 2026-09-02 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images erlang27-27.3.4.17-0.1.hum1@aarch64, erlang27-27.3.4.17-0.1.hum1@src, erlang27-27.3.4.17-0.1.hum1@x86_64 +47

Fixed in the same release

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

  • Release ·

    Erlang OTP 27.3.4.17, 28.5.0.6, 29.0.6

    4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW

    Other records, highest priority first

    • TI-2026-42572 uri_string does not bound the port component of a URI before integer conversionPriority LOW 38
    • TI-2026-51405 inets, httpd: HTTP Request Smuggling via Whitespace-Before-Colon Header Dropping iPriority LOW 37
    • TI-2026-49189 eldap does not bound the port component of a referral URL before integer conversionPriority LOW 29
    Show all 4 records →
  • Release ·

    Erlang OTP 9.3.2.7, 9.6.2.3, 9.7.2

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-51405 inets, httpd: HTTP Request Smuggling via Whitespace-Before-Colon Header Dropping iPriority LOW 37
    Show all 2 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Hardened ImagesFixed RHSA-2026:62531

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-70399

References

Patch 3

Advisory 1

Other 3

  • TI-2025-23504 Erlang/OTP SSH Vulnerable to Pre-Authentication RCE KEVCVSS 3.1CRITICAL 10.0
  • TI-2026-48954 httpd parks a request worker indefinitely on a malformed chunk size sent after the headers CVSS 4.0HIGH 8.7
  • TI-2023-26623 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… CVSS 3.1MEDIUM 5.9
  • TI-2026-71037 Path traversal in rebar3 via unvalidated dependency app names CVSS 4.0HIGH 7.5
  • TI-2024-36042 ssl fails to validate incorrect extened key usage CVSS 3.1MEDIUM 5.5
  • TI-2020-10791 Rebar3 versions 3.0.0-beta.3 to 3.13.2 are vulnerable to OS command injection via URL… CVSS 3.1CRITICAL 9.8
See all 80 →

Sources

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