GHSA-cxpw-2g23-2vgw OpenClaw: ACP prompt-size checks missing in local stdio bridge could reduce responsiveness with very large inputs

• npm openclaw: < 2026.2.19 → fixed in 2026.2.19

Vulnerability The ACP bridge accepted very large prompt text blocks and could assemble oversized prompt payloads before forwarding them to `chat.send`. Because ACP runs over local stdio, this mainly affects local ACP clients (for example IDE integrations) that send unusually large inputs. Affected Packages / Versions • Package: `openclaw` (npm) • Affected versions: `<= 2026.2.17` • Patched version: `2026.2.18` (planned next release) Impact • Local ACP sessions may become less responsive when very large prompts are submitted • Larger-than-expected model usage/cost when oversized text is forwarded • No privilege escalation and no direct remote attack path in the default ACP model Affected Components • `src/acp/event-mapper.ts` • `src/acp/translator.ts` Remediation • Enforce a 2 MiB prompt-text limit before concatenation • Count inter-block newline separator bytes during pre-concatenation size checks • Keep final outbound message-size validation before `chat.send` • Avoid stale active-run session state when oversized prompts are rejected • Add regression tests for oversize rejection and active-run cleanup Fix Commit(s) • `732e53151e8fbdfc0501182ddb0e900878bdc1e3` • `ebcf19746f5c500a41817e03abecadea8655654a` • `63e39d7f57ac4ad4a5e38d17e7394ae7c4dd0b9c` Thanks @aether-ai-agent for reporting.