CVE-2026-58226

What it is

Inefficient Algorithmic Complexity vulnerability in elixir-mint hpax allows unauthenticated denial-of-service via unbounded HPACK integer decoding. hpax decodes HPACK variable-length integers with no upper bound on the decoded value or the number of continuation octets. 'Elixir.HPAX.Types':decode_remaining_integer/3 accumulates the integer as int + (value <<< m), shifting by 7 more bits for each continuation octet and stopping only on a terminating octet or truncated input, never because the integer grew too large. Because BEAM integers are arbitrary precision, a run of N continuation octets builds an O(N)-bit bignum and re-adds into an ever-larger bignum on each step, so the total decoding cost is superlinear (about O(N^2)). An unauthenticated attacker who can send an HTTP/2 header block to a server using this decoder (reached through the 'Elixir.HPAX':decode/2 entry point) can supply a small header block that forces a large, attacker-controlled amount of CPU (and transient memory), a denial-of-service amplification. This issue affects hpax from 0.1.1 before 1.0.4.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-06 11:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-25 20:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.6% in the next 30 days (EPSS).
• Severity: 8.7 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-06 11:16 UTC

Last modified

2026-10-25 20:10 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-407

Record status

Deferred

Attack profile CVSS 4.0 · 8.7

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-58226.md and follow it. Check whether this project is affected by CVE-2026-58226. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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