CHW-2305 ChecksumMismatch

artifact checksum mismatch: upstream-declared hash disagrees with downloaded bytes; inspect the X-Chainsaw-Checksum-Mismatch header or raise CHAINSAW_CHECKSUM_MODE=log if this is a known-false-posi…

Default message: artifact checksum mismatch: upstream-declared hash disagrees with downloaded bytes; inspect the X-Chainsaw-Checksum-Mismatch header or raise CHAINSAW_CHECKSUM_MODE=log if this is a known-false-positive mirror
HTTP status: 403 (client)
Reason: CHECKSUM_MISMATCH

Problem. A download was refused because the artifact’s computed hash did not match the registry-declared hash. Cause. The proxy re-hashed the bytes and detected an upstream / network disagreement; under CHAINSAW_CHECKSUM_MODE=quarantine (the default) or block the request fails. The response carries X-Chainsaw-Checksum-Mismatch: <ecosystem>/<declared>/<actual> so operators can audit the disagreement without re-downloading. Fix. Inspect the header to confirm the mismatch, re-fetch from a healthy mirror, or set CHAINSAW_CHECKSUM_MODE=log if this is a known-false-positive mirror. HTTP 403 — a checksum mismatch is a policy decision (“do not serve a tampered artifact”), not a transient availability problem, so it is terminal and CI runners must not retry it.