Unauthenticated denial-of-service via unbounded HPACK integer decoding in hpax
Summary
| CVE | CVE-2026-58226 |
|---|---|
| State | PUBLISHED |
| Assigner | EEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-06 11:16:31 UTC |
| Updated | 2026-07-06 19:37:48 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 8.7 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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
Problem Types: CWE-407 | CWE-407 CWE-407 Inefficient Algorithmic Complexity
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | Secondary | 8.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 8.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
NoneAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Elixir-mint | Hpax | affected 0.1.1 1.0.4 semver | Not specified |
| CNA | Elixir-mint | Hpax | affected 56db437a7e2c515e3bdd770ac7947b02cd2390d0 1ba4bb2dc91e80089cf89c73970ac3ded76f17eb git | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| osv.dev/vulnerability/EEF-CVE-2026-58226 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | osv.dev | |
| github.com/elixir-mint/hpax/security/advisories/GHSA-jj2p-32j7-whj2 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | github.com | |
| github.com/elixir-mint/hpax/commit/1ba4bb2dc91e80089cf89c73970ac3ded76f17eb | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| cna.erlef.org/cves/CVE-2026-58226.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | cna.erlef.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Peter Ullrich (en)
CNA: Andrea Leopardi (en)
CNA: Jonatan Männchen / EEF (en)
CNA: Eric Meadows-Jönsson (en)
There are currently no legacy QID mappings associated with this CVE.