Permission bypass in Phi lets spawned sub-agents write outside workspace
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
Phi from 0.3.0 through 0.28.4 by pulseaiclub contains a permission bypass where spawned sub-agents escape the workspace_only_writes and readonly restrictions. The agent_spawn function accepts an unchecked workdir, an incorrect authorization flaw (CWE-863). An unauthenticated remote attacker can plant prompt-injected instructions in processed content so the agent spawns a worker rooted elsewhere, causing file writes the user has not approved anywhere the user can write, though exploitation requires user interaction. CISA SSVC rates exploitation as proof of concept, but no public exploit is linked and the flaw is not in CISA KEV.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
Phi 0.3.0 through 0.28.4 contains a permission bypass vulnerability that allows spawned sub-agents to escape workspace_only_writes and readonly mode by supplying an unchecked workdir to agent_spawn. Attackers can plant prompt-injected instructions in processed content so the agent spawns a worker rooted elsewhere, causing unapproved file writes anywhere the user can write.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| pulseaiclub | phi | 0.3.0 – 0.28.4 | — | No fix listed | CNA |
- phi Vendorpulseaiclub Affected 0.3.0 – 0.28.4 Fixed in — No fix listed CNA
Remediation
The sources list no fixed version for Phi. Review agent_spawn usage and restrict the workdir to the intended workspace until a fix is available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Timeline
- 2026-10-11 Threatist record created from CVE-2026-108595
- 2026-10-11 Alias added: GHSA-x8rp-9mrq-5584
- 2026-10-11 Priority changed: MEDIUM → LOW
- 2026-10-13 CISA SSVC decision points changed
- 2026-10-13 Priority changed: LOW → MEDIUM
References
More pulseaiclub vulnerabilities
- TI-2026-70583 Symlink path check bypass in phi lets writes escape the workspace CVSS 4.0MEDIUM 5.7
Sources
- CVE-2026-108595 · CVE Program
- CVE-2026-108595 · NVD
- FIRST EPSS
- GHSA-x8rp-9mrq-5584 · GitHub Advisory Database · CC BY 4.0
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