CVE-2026-42788: CWE-770 Allocation of Resources Without Limits or Throttling in mtrudel bandit
Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated memory exhaustion via oversized HTTP/2 frames. 'Elixir.Bandit.HTTP2.Frame':deserialize/2 in lib/bandit/http2/frame.ex checks the SETTINGS_MAX_FRAME_SIZE limit only after pattern-matching payload::binary-size(length), which requires the entire frame body to be present in memory before either the accept or reject clause can fire. A peer that announces a frame length up to the 24-bit maximum (~16 MiB) causes the server to buffer that entire body before the size guard is evaluated, regardless of the max_frame_size negotiated during the HTTP/2 handshake (default 16 KiB per RFC 9113). An unauthenticated attacker holding many concurrent connections can force the server to buffer far more memory than the negotiated frame size limit should permit, leading to memory pressure and potential denial of service. This issue affects bandit: from 0.3.6 before 1.11.0.
AI Analysis
Technical Summary
The vulnerability in mtrudel bandit's HTTP/2 frame deserialization occurs because the function 'Elixir.Bandit.HTTP2.Frame':deserialize/2 buffers the entire frame payload in memory before checking if it exceeds the SETTINGS_MAX_FRAME_SIZE limit. Although the HTTP/2 protocol negotiation sets a maximum frame size (default 16 KiB per RFC 9113), the server accepts frames up to the 24-bit maximum length (~16 MiB) before rejecting them. An unauthenticated attacker can exploit this by opening many concurrent connections and sending large frames, causing excessive memory allocation and potential denial of service. This affects bandit versions from 0.3.6 up to but not including 1.11.0.
Potential Impact
An unauthenticated attacker can cause the server to allocate excessive memory by sending oversized HTTP/2 frames, leading to memory exhaustion and potential denial of service. This can degrade service availability but does not require authentication or user interaction. There is no indication of data compromise or code execution from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround is documented in the provided data. Until a patch is available, limiting the number of concurrent connections or deploying upstream protections to restrict frame sizes may help mitigate impact, but these are not vendor-recommended mitigations. Monitor vendor communications for an official fix.
CVE-2026-42788: CWE-770 Allocation of Resources Without Limits or Throttling in mtrudel bandit
Description
Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated memory exhaustion via oversized HTTP/2 frames. 'Elixir.Bandit.HTTP2.Frame':deserialize/2 in lib/bandit/http2/frame.ex checks the SETTINGS_MAX_FRAME_SIZE limit only after pattern-matching payload::binary-size(length), which requires the entire frame body to be present in memory before either the accept or reject clause can fire. A peer that announces a frame length up to the 24-bit maximum (~16 MiB) causes the server to buffer that entire body before the size guard is evaluated, regardless of the max_frame_size negotiated during the HTTP/2 handshake (default 16 KiB per RFC 9113). An unauthenticated attacker holding many concurrent connections can force the server to buffer far more memory than the negotiated frame size limit should permit, leading to memory pressure and potential denial of service. This issue affects bandit: from 0.3.6 before 1.11.0.
CVSS v4.0
Score 6.9medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in mtrudel bandit's HTTP/2 frame deserialization occurs because the function 'Elixir.Bandit.HTTP2.Frame':deserialize/2 buffers the entire frame payload in memory before checking if it exceeds the SETTINGS_MAX_FRAME_SIZE limit. Although the HTTP/2 protocol negotiation sets a maximum frame size (default 16 KiB per RFC 9113), the server accepts frames up to the 24-bit maximum length (~16 MiB) before rejecting them. An unauthenticated attacker can exploit this by opening many concurrent connections and sending large frames, causing excessive memory allocation and potential denial of service. This affects bandit versions from 0.3.6 up to but not including 1.11.0.
Potential Impact
An unauthenticated attacker can cause the server to allocate excessive memory by sending oversized HTTP/2 frames, leading to memory exhaustion and potential denial of service. This can degrade service availability but does not require authentication or user interaction. There is no indication of data compromise or code execution from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround is documented in the provided data. Until a patch is available, limiting the number of concurrent connections or deploying upstream protections to restrict frame sizes may help mitigate impact, but these are not vendor-recommended mitigations. Monitor vendor communications for an official fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- EEF
- Date Reserved
- 2026-04-29T18:06:33.251Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f5124bcbff5d86105840f0
Added to database: 5/1/2026, 8:51:23 PM
Last enriched: 5/27/2026, 8:06:33 PM
Last updated: 6/15/2026, 7:01:38 PM
Views: 87
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