Review reviewHigh

CVE-2026-10725

CRUX Protocol::HTTP2, protocol::http2

Protocol::HTTP2 versions before 1.13 for Perl is vulnerable to a HTTP/2 Bomb. Protocol::HTTP2's inbound HPACK path has no header-list size limit, so a small HTTP/2 request can expand into large server memory (the "HTTP/2 bomb"). The headers_decode method materialises a full key+value copy per indexed reference with no running size check, and the stream_header_block_add method appends (since version 1.12) every CONTINUATION frame to the per-stream buffer unbounded. MAX_HEADER_LIST_SIZE (default 65536) is advertised in SETTINGS but never consulted on decode. It is absent from the decoder and...

CVSS: 7.5
EPSS: 0.41%
CISA KEV: Not listed
Published: 2026.06.06

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.41%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: CRUX Protocol::HTTP2, protocol::http2
Affected versions: < 1.13
Fixed versions: 1.13

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that CRUX Protocol::HTTP2, protocol::http2 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-409