CVE-2026-113436 json
Quadratic bignum parsing of Content-Length and Host port values in Bandit
published 2026-10-26 13 d ago modified 2026-10-26 13 d ago also EEF-CVE-2026-113436 , GHSA-29cr-8477-rg6r , EUVD-2026-109823
- cvss
- 8.7
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 49%
- public exploits
- 0
- none known
Summary
Inefficient Algorithmic Complexity vulnerability in the header integer parser of mtrudel bandit allows an unauthenticated remote attacker to consume server CPU via a content-length value or a Host or :authority port made of thousands of digits.
Bandit.Headers.parse_integer/2 in lib/bandit/headers.ex builds the number one digit at a time with no limit on the digit count, allocating a new bignum at each step, so one value costs time quadratic in its length. It runs on raw request input over HTTP/1 and HTTP/2, before any range check. Over HTTP/2, a 4,000-digit value can be stored once in the HPACK dynamic table and re-sent on each new stream for about one byte: 124 KB of traffic kept the server busy for 27.9 s.
This issue affects bandit: from 1.0.0-pre.7 before 1.14.0.
Patch / fix
- hex bandit 1.14.0
- mtrudel bandit 1.14.0
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 13 d ago
Exploit prediction
0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | 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 |
| CNA | 4.0 | 8.7 | 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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| hex | bandit | >=1.0.0-pre.7, <1.14.0 |
1.14.0 |
Affected products
- mtrudel bandit
Classification
- Weakness
-
- CWE-407 Inefficient Algorithmic Complexity
References
-
github.com
/mtrudel/bandit/commit/e0c8c0c30af9b0f57d8aafac37ddd9294363a8be
related, web
-
github.com
/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a
patch
-
github.com
/mtrudel/bandit/security/advisories/GHSA-29cr-8477-rg6r
vendor-advisory, related, advisory
-
cna.erlef.org
/cves/CVE-2026-113436.html
related, web
-
osv.dev
/vulnerability/EEF-CVE-2026-113436
related
-
hex.pm
/packages/bandit
package
Sources
- CVE List CVE-2026-113436
- NVD CVE-2026-113436
- OSV EEF-CVE-2026-113436
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