CVE-2026-59246: Zero-length HTTP/2 CONTINUATION frames bypass Mint's header-block byte-size cap and exhaust client memory
Noroxi assessment
Priority: Monitor (action score 25/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.50% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: elixir-mint mint 1.9.2, 5779de1666344b32aefc4354184ea07f902f73ce.
Low priority for now. Upgrade to elixir-mint mint 1.9.2, 5779de1666344b32aefc4354184ea07f902f73ce or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service. The Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper. A malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination. This issue affects mint: from 0.1.0 before 1.9.2.
- Published
- Jul 14, 2026
- Updated
- Oct 24, 2026
- EPSS
- 0.5% · 42th percentile
- CWE
- CWE-770
Report tools
Action score
25
Monitor
Low priority for now.
- CVSS
- 25 / 40 · 6.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · EEF
- 6.3
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.
elixir-mint mint
- 0.1.0 and later · before 1.9.2affected · semver
- 596ca4304504be68939c4929e0831557097962b8 and later · before 5779de1666344b32aefc4354184ea07f902f73ceaffected · git
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Hex | mint | from 0.1.0 · before 1.9.2 | 1.9.2 |
Same product
elixir-mint: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-56810mint buffers an entire chunked response chunk in memory in Mint.HTTP1.decode_body/534Monitor
- CVE-2026-91043HPACK-indexed cookie fields in Mint HTTP/2 responses bypass max_header_list_size and exhaust client memory32Monitor
- CVE-2026-82728Unbounded HTTP/1 status-line and chunk-extension buffering in Mint causes memory-exhaustion DoS32Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-49754Jun 2, 2026 · HTTP/2 CONTINUATION flood in Mint client via unbounded header-block accumulation32Monitor
- ← EarlierCVE-2026-58229Jul 14, 2026 · Unbounded HTTP/1 response-header and chunked-trailer accumulation in Mint causes memory-exhaustion DoS32Monitor
- Later →CVE-2026-59249Jul 16, 2026 · Sign-tolerant HTTP/1 chunk-size parser in Mint enables response smuggling against strict intermediaries on pooled connections25Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| elixir-mint mint | 1.9.2 | Vendor (CNA) |
| elixir-mint mint | 5779de1666344b32aefc4354184ea07f902f73ce | Vendor (CNA) |
| Hex:mint | 1.9.2 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Eric Meadows-Jönssonremediation reviewer
- Andrea Leopardiremediation developer
- zx (Jace)finder
- Jonatan Männchen / EEFanalyst
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-568108 days apartmint buffers an entire chunked response chunk in memory in Mint.HTTP1.decode_body/534Monitor
- CVE-2026-582290 days apartUnbounded HTTP/1 response-header and chunked-trailer accumulation in Mint causes memory-exhaustion DoS32Monitor
- CVE-2026-4886242 days apartUnbounded conn.streams growth in Mint HTTP/2 client via unenforced PUSH_PROMISE concurrency32Monitor
- CVE-2026-4975442 days apartHTTP/2 CONTINUATION flood in Mint client via unbounded header-block accumulation32Monitor
- CVE-2026-8272852 days apartUnbounded HTTP/1 status-line and chunk-extension buffering in Mint causes memory-exhaustion DoS32Monitor
- CVE-2026-9104376 days apartHPACK-indexed cookie fields in Mint HTTP/2 responses bypass max_header_list_size and exhaust client memory32Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-770 · Allocation of Resources Without Limits or ThrottlingCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- FloodingCAPEC-125likelihood: High · Medium
- Excessive AllocationCAPEC-130likelihood: Medium · Medium
- XML Ping of the DeathCAPEC-147likelihood: Low · Medium
- Exponential Data ExpansionCAPEC-197likelihood: High · Medium
- Serialized Data Parameter BlowupCAPEC-229likelihood: High · High
- Serialized Data with Nested PayloadsCAPEC-230likelihood: Medium · High
- Oversized Serialized Data PayloadsCAPEC-231likelihood: Medium · High
- HTTP DoSCAPEC-469Low
ATT&CK techniques
- Network Denial of Service:Direct Network FloodT1498.001
- Network Denial of Service:Reflection AmplificationT1498.002
- Endpoint Denial of ServiceT1499
- Endpoint Denial of Service: OS Exhaustion FloodT1499.001
- Endpoint Denial of Service:Service Exhaustion FloodT1499.002
- Endpoint Denial of Service:Application Exhaustion FloodT1499.003
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (3 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.