WebSocket 1-byte continuation frames bypass `max_fragmented_message_size` in Bandit
Impact
Bandit WebSocket is vulnerable to resource exhaustion due to unauthenticated remote attackers sending many 1-byte continuation frames, affecting versions 1.11.0 before 1.14.0. This can exhaust server memory. The issue is due to the lack of limits on the number of fragments.
Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.What to do
Lower websocket_options: [max_fragmented_message_size: ...] to the largest fragmented message the application needs, for example 65_536. Memory per connection stays at about 150 times this limit, so a lower limit lowers the ceiling.
Affected packages
Affected products
Vendor version evidence. Product records are separate from automatic dependency matching.
mtrudel · EEF
bandit
1 range
mtrudel · EEF
bandit
Package identity
pkg:hex/banditExplore bandit →Identity supplied by EEF. Version matching requires compatible range evidence.
Compare with this publisher’s ranges. This does not inspect your installation.
affected
1.11.0 → before 1.14.0
semver versions
Other versions: unaffected
Product identifiers (CPE)
cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*mtrudel · EEF
bandit
1 range
mtrudel · EEF
bandit
Package identity
pkg:github/mtrudel/banditIdentity supplied by EEF. Version matching requires compatible range evidence.
Compare with this publisher’s ranges. This does not inspect your installation.
affected
21612c7c7b1ce43eccd36d3af3a2299d23513667 → before 220b9dfd27f9a21305be2afc75cbe585ddc24e7a
git versions
Other versions: unaffected
Product identifiers (CPE)
cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*Original source description
Allocation of Resources Without Limits or Throttling vulnerability in the WebSocket fragment reassembly of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory via a fragmented message made of many 1-byte continuation frames.
Bandit.WebSocket.Connection checks max_fragmented_message_size against the payload bytes received, but keeps every non-final continuation frame as a new list cell around its own binary, and nothing limits the number of fragments. A 1-byte fragment costs 7 bytes on the wire but about 150 to 170 bytes of server memory, so one connection can hold about 150 times the configured limit, roughly 1.2 to 1.4 GB at the default 8 MB. Ping frames between fragments keep the connection alive past the idle timeout.
This issue affects bandit: from 1.11.0 before 1.14.0.
Inside the record
Evidence available
Describes the evidence in this view, not whether the product is safe.
Original records
CVE-2026-114213View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.
cve.new JSON →Underlying weaknesses
The source’s classification of what caused the vulnerability.
Environment requirements
These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.
EEF · platform conditions
All conditions must hold
Any condition may hold
Vulnerable product
cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*From (inclusive): 1.11.0
Before: 1.14.0
Original applicability statements
[
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*",
"versionEndExcluding": "1.14.0",
"versionStartIncluding": "1.11.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "AND"
}
]Contributing organizations · 2
Assigning organization
Additional data publisher
What changed
Follow changesLarge field values are marked as truncated previews. Original source snapshots remain retained.