p PatchFirst

CVE-2026-55951

CVE-2026-55951 · httpc memory exhaustion via unbounded response header accumulation

This page contains facts from public vulnerability sources. Check the original advisory before updating.

The Erlang/OTP httpc HTTP client does not enforce a limit on the total size of response headers received from a server. The max_header_size option defaults to nolimit, and httpc_response:parse_headers/6 accumulates every header into a list before the length check runs (which only fires after the terminating CRLF CRLF is received). A malicious or compromised HTTP server can send an arbitrarily large number of headers, or headers with very large values, causing the client process to allocate unbounded memory until the system runs out of memory or the BEAM VM crashes. A proof-of-concept server sending 100,000 headers of roughly 4000 bytes each caused the client VM to allocate over 13 GB of memory in under 30 seconds. Any application using httpc:request/4,5 to connect to untrusted servers is affected. No authentication is required: any server the client connects to (including via a redirect or man-in-the-middle) can trigger the exhaustion. 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. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

CVSS 8.2 · High · EPSS 0.7% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • otp

    Versions
    • ≥ 0, < 17.0: Unknown (otp)
    • ≥ 17.0, < 27.3.4.17: Affected (otp)
    • ≥ 28.0, < 28.5.0.6: Affected (otp)
    • ≥ 29.0, < 29.0.6: Affected (otp)

    Update to 27.3.4.17; Update to 28.5.0.6; Update to 29.0.6

  • otp

    Versions
    • ≥ 0, < 5.10: Unknown (otp)
    • ≥ 5.10, < 9.3.2.7: Affected (otp)
    • ≥ 9.4, < 9.6.2.3: Affected (otp)
    • ≥ 9.7, < 9.7.2: Affected (otp)

    Update to 9.3.2.7; Update to 9.6.2.3; Update to 9.7.2

  • otp

    Versions
    • ≥ 84adefa331c4159d432d22840663c38f155cd4c1: Affected; ≥ aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d: Not affected; ≥ e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa: Not affected (git)

    No fix published

  • erlang Debian:12

    Versions
    • 1:25.2.3+dfsg-1
    • 1:25.2.3+dfsg-1+deb12u1
    • 1:25.2.3+dfsg-1+deb12u2
    • 1:25.2.3+dfsg-1+deb12u3
    • 1:25.2.3+dfsg-1+deb12u4
    • 1:25.3.2.10+dfsg-1
    • 1:25.3.2.10+dfsg-2
    • 1:25.3.2.11+dfsg-1
    • 1:25.3.2.12+dfsg-1
    • 1:25.3.2.12+dfsg-2
    • 1:25.3.2.12+dfsg-3
    • 1:25.3.2.8+dfsg-1
    • 1:26.0+dfsg-1
    • 1:26.0.1+dfsg-1
    • 1:26.0.2+dfsg-1
    • 1:26.0~rc2+dfsg-1
    • 1:26.0~rc3+dfsg-1
    • 1:26.1.2+dfsg-1
    • 1:26.2.1+dfsg-1
    • 1:26.2.4+dfsg-1
    • 1:27.0+dfsg-1
    • 1:27.0.1+dfsg-1
    • 1:27.0.1+dfsg-2
    • 1:27.0.1+dfsg-3
    • 1:27.0~rc3+dfsg-1
    • 1:27.0~rc3+dfsg-2
    • 1:27.0~rc3+dfsg-3
    • 1:27.0~rc3+dfsg-4
    • 1:27.1.2+dfsg-1
    • 1:27.2+dfsg-1
    • 1:27.2+dfsg-2
    • 1:27.2+dfsg-3~exp1
    • 1:27.2.1+dfsg-1
    • 1:27.2.1+dfsg-2
    • 1:27.2.2+dfsg-1
    • 1:27.2.3+dfsg-1
    • 1:27.2.4+dfsg-1
    • 1:27.3+dfsg-1
    • 1:27.3.1+dfsg-1
    • 1:27.3.2+dfsg-1
    • 1:27.3.3+dfsg-1
    • 1:27.3.4+dfsg-1
    • 1:27.3.4.1+dfsg-1
    • 1:27.3.4.10+dfsg-1
    • 1:27.3.4.11+dfsg-1
    • 1:27.3.4.11+dfsg-2
    • 1:27.3.4.11+dfsg-3
    • 1:27.3.4.11+dfsg-4
    • 1:27.3.4.11+dfsg-5
    • 1:27.3.4.11+dfsg-6
    • 1:27.3.4.11+dfsg-7
    • 1:27.3.4.12+dfsg-1
    • 1:27.3.4.3+dfsg-1
    • 1:27.3.4.4+dfsg-1
    • 1:27.3.4.6+dfsg-1
    • 1:27.3.4.8+dfsg-1
    • 1:27.3.4.9+dfsg-1
    • 1:28.0+dfsg-1
    • 1:28.0.1+dfsg-1
    • 1:28.0.2+dfsg-1
    • 1:28.0.4+dfsg-1
    • 1:28.1.1+dfsg-1
    • 1:28.2+dfsg-1
    • 1:28.3+dfsg-1
    • 1:28.3.1+dfsg-1
    • 1:29.0+dfsg-1
    • 1:29.0+dfsg-2
    • 1:29.0.1+dfsg-1
    • 1:29.0.2+dfsg-1
    • 1:29.0.3+dfsg-1
    • 1:29.0.4+dfsg-1
    • 1:29.0.6+dfsg-1
    • 1:29.0~rc1+dfsg-1
    • 1:29.0~rc1+dfsg-2
    • 1:29.0~rc2+dfsg-1
    • 1:29.0~rc3+dfsg-1
    • 1:29.0~rc3+dfsg-2
    • 1:29.0~rc3+dfsg-3
    • 1:29.0~rc3+dfsg-4
    • 1:29.1.1+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • erlang Debian:13

    Versions
    • 1:27.3.4.1+dfsg-1
    • 1:27.3.4.1+dfsg-1+deb13u1
    • 1:27.3.4.1+dfsg-1+deb13u2
    • 1:27.3.4.1+dfsg-1+deb13u3
    Affected ranges
    • ECOSYSTEM: < 1:27.3.4.1+dfsg-1+deb13u4

    Update to 1:27.3.4.1+dfsg-1+deb13u4

  • erlang Debian:14

    Versions
    • 1:27.3.4.1+dfsg-1
    • 1:27.3.4.10+dfsg-1
    • 1:27.3.4.11+dfsg-1
    • 1:27.3.4.11+dfsg-2
    • 1:27.3.4.11+dfsg-3
    • 1:27.3.4.11+dfsg-4
    • 1:27.3.4.11+dfsg-5
    • 1:27.3.4.11+dfsg-6
    • 1:27.3.4.11+dfsg-7
    • 1:27.3.4.12+dfsg-1
    • 1:27.3.4.3+dfsg-1
    • 1:27.3.4.4+dfsg-1
    • 1:27.3.4.6+dfsg-1
    • 1:27.3.4.8+dfsg-1
    • 1:27.3.4.9+dfsg-1
    • 1:28.0+dfsg-1
    • 1:28.0.1+dfsg-1
    • 1:28.0.2+dfsg-1
    • 1:28.0.4+dfsg-1
    • 1:28.1.1+dfsg-1
    • 1:28.2+dfsg-1
    • 1:28.3+dfsg-1
    • 1:28.3.1+dfsg-1
    • 1:29.0+dfsg-1
    • 1:29.0+dfsg-2
    • 1:29.0.1+dfsg-1
    • 1:29.0.2+dfsg-1
    • 1:29.0.3+dfsg-1
    • 1:29.0.4+dfsg-1
    • 1:29.0~rc1+dfsg-1
    • 1:29.0~rc1+dfsg-2
    • 1:29.0~rc2+dfsg-1
    • 1:29.0~rc3+dfsg-1
    • 1:29.0~rc3+dfsg-2
    • 1:29.0~rc3+dfsg-3
    • 1:29.0~rc3+dfsg-4
    Affected ranges
    • ECOSYSTEM: < 1:29.0.6+dfsg-1

    Update to 1:29.0.6+dfsg-1

  • erlang Ubuntu:Pro:14.04:LTS

    Versions
    • 1:16.b.1-dfsg-4ubuntu1
    • 1:16.b.2-dfsg-1ubuntu1
    • 1:16.b.2-dfsg-2ubuntu1
    • 1:16.b.3-dfsg-1ubuntu1
    • 1:16.b.3-dfsg-1ubuntu2
    • 1:16.b.3-dfsg-1ubuntu2.1
    • 1:16.b.3-dfsg-1ubuntu2.2
    • 1:16.b.3-dfsg-1ubuntu2.2+esm1
    Affected ranges
    • ECOSYSTEM: < 1:16.b.3-dfsg-1ubuntu2.2+esm2

    Update to 1:16.b.3-dfsg-1ubuntu2.2+esm2

  • erlang Ubuntu:Pro:16.04:LTS

    Versions
    • 1:18.0-dfsg-1ubuntu1
    • 1:18.0-dfsg-1ubuntu2
    • 1:18.2-dfsg-2ubuntu1
    • 1:18.3-dfsg-1ubuntu1
    • 1:18.3-dfsg-1ubuntu2
    • 1:18.3-dfsg-1ubuntu3
    • 1:18.3-dfsg-1ubuntu3.1
    • 1:18.3-dfsg-1ubuntu3.1+esm1
    • 1:18.3-dfsg-1ubuntu3.1+esm2
    Affected ranges
    • ECOSYSTEM: < 1:18.3-dfsg-1ubuntu3.1+esm3

    Update to 1:18.3-dfsg-1ubuntu3.1+esm3

  • erlang Ubuntu:Pro:18.04:LTS

    Versions
    • 1:20.0.4+dfsg-1ubuntu1
    • 1:20.1.2+dfsg-1ubuntu1
    • 1:20.1.3+dfsg-1ubuntu1
    • 1:20.1.4+dfsg-1ubuntu1
    • 1:20.1.5+dfsg-1ubuntu1
    • 1:20.1.6+dfsg-1ubuntu1
    • 1:20.1.7+dfsg-1ubuntu1
    • 1:20.2.1+dfsg-1ubuntu1
    • 1:20.2.2+dfsg-1ubuntu1
    • 1:20.2.2+dfsg-1ubuntu2
    • 1:20.2.2+dfsg-1ubuntu2+esm1
    • 1:20.2.2+dfsg-1ubuntu2+esm2
    Affected ranges
    • ECOSYSTEM: < 1:20.2.2+dfsg-1ubuntu2+esm3

    Update to 1:20.2.2+dfsg-1ubuntu2+esm3

  • erlang Ubuntu:Pro:20.04:LTS

    Versions
    • 1:22.0.7+dfsg-1build1
    • 1:22.2+dfsg-1
    • 1:22.2.1+dfsg-1
    • 1:22.2.2+dfsg-1
    • 1:22.2.3+dfsg-1
    • 1:22.2.3+dfsg-2
    • 1:22.2.4+dfsg-1
    • 1:22.2.7+dfsg-1
    • 1:22.2.7+dfsg-1ubuntu0.2
    • 1:22.2.7+dfsg-1ubuntu0.3
    • 1:22.2.7+dfsg-1ubuntu0.4
    • 1:22.2.7+dfsg-1ubuntu0.5
    • 1:22.2.7+dfsg-1ubuntu0.5+esm1
    Affected ranges
    • ECOSYSTEM: < 1:22.2.7+dfsg-1ubuntu0.5+esm2

    Update to 1:22.2.7+dfsg-1ubuntu0.5+esm2

  • erlang Ubuntu:22.04:LTS

    Versions
    • 1:23.2.6+dfsg-1build1
    • 1:24.1.1+dfsg-1
    • 1:24.1.4+dfsg-1
    • 1:24.1.5+dfsg-1
    • 1:24.1.5+dfsg-1ubuntu1
    • 1:24.2+dfsg-1
    • 1:24.2.1+dfsg-1
    • 1:24.2.1+dfsg-1ubuntu0.1
    • 1:24.2.1+dfsg-1ubuntu0.2
    • 1:24.2.1+dfsg-1ubuntu0.3
    • 1:24.2.1+dfsg-1ubuntu0.4
    • 1:24.2.1+dfsg-1ubuntu0.5
    • 1:24.2.1+dfsg-1ubuntu0.6
    Affected ranges
    • ECOSYSTEM: < 1:24.2.1+dfsg-1ubuntu0.7

    Update to 1:24.2.1+dfsg-1ubuntu0.7

  • erlang Ubuntu:24.04:LTS

    Versions
    • 1:25.2.3+dfsg-1
    • 1:25.3.2.8+dfsg-1
    • 1:25.3.2.8+dfsg-1ubuntu1
    • 1:25.3.2.8+dfsg-1ubuntu3
    • 1:25.3.2.8+dfsg-1ubuntu4
    • 1:25.3.2.8+dfsg-1ubuntu4.1
    • 1:25.3.2.8+dfsg-1ubuntu4.2
    • 1:25.3.2.8+dfsg-1ubuntu4.3
    • 1:25.3.2.8+dfsg-1ubuntu4.4
    • 1:25.3.2.8+dfsg-1ubuntu4.5
    • 1:25.3.2.8+dfsg-1ubuntu4.6
    Affected ranges
    • ECOSYSTEM: < 1:25.3.2.8+dfsg-1ubuntu4.7

    Update to 1:25.3.2.8+dfsg-1ubuntu4.7

  • erlang Ubuntu:26.04:LTS

    Versions
    • 1:27.3.4.1+dfsg-1build1
    • 1:27.3.4.3+dfsg-1
    • 1:27.3.4.4+dfsg-1
    • 1:27.3.4.6+dfsg-1
    Affected ranges
    • ECOSYSTEM: < 1:27.3.4.6+dfsg-1ubuntu0.1

    Update to 1:27.3.4.6+dfsg-1ubuntu0.1

Original sources

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