AI agents exploited PaperCut flaws on 440 servers

A Codex and DeepSeek campaign chained two PaperCut CVEs and compromised at least 440 servers at 395 organizations in 48 countries.

GreyNoise and Hunt.io, and Blackpoint Cyber according to GBHackers, reported a campaign using an OpenAI Codex harness with a DeepSeek model against internet-facing PaperCut NG/MF servers. The operators chained CVE-2026-81578 (CVSS 8.8), described as an authentication bypass or unauthenticated setting changes, with CVE-2026-82078 (CVSS 9.4), an unsafe dynamic class-loading flaw, to execute code in the PaperCut process. Both reports say at least 440 instances tied to 395 organizations in 48 countries were compromised. GBHackers alone describes a likely Russian-speaking actor using hundreds of AI agents, domain-administrator access at 12 organizations, credential harvesting from 280 instances, theft of Windows registry and configuration-file secrets, and chisel pivots as well as reverse SOCKS. Cyber Security News, citing GreyNoise and Hunt.io, instead dates lab activity to August 31, 2026, a live target in under four hours, 1,005 recon hosts, and 46 Active Directory domains, and does not repeat the Russian-speaking or Blackpoint claims. PaperCut’s fixed maintenance releases are 26.0.5, 25.0.13, and 24.1.10; one report also advises restricting exposed APIs.

• GreyNoise and Hunt.io, with Blackpoint Cyber also cited by GBHackers, reported exploitation of internet-facing PaperCut NG/MF servers.
• CVE-2026-81578 (CVSS 8.8; authentication bypass or unauthenticated setting changes) was chained with CVE-2026-82078 (CVSS 9.4; unsafe dynamic class loading) for code execution.
• At least 440 instances at 395 organizations in 48 countries were compromised.
• The operator used an OpenAI Codex harness with a DeepSeek model; GBHackers alone calls the actor likely Russian-speaking and says hundreds of AI agents were used.
• GBHackers reports domain-administrator access at 12 organizations, credential harvesting from 280 instances, Windows registry and configuration secrets, and reverse SOCKS plus chisel pivots.
• Cyber Security News, citing Hunt.io, reports 1,005 recon hosts, 46 Active Directory domains, lab activity starting August 31, 2026, and a live target in under four hours.
• Fixed PaperCut NG/MF maintenance releases are 26.0.5, 25.0.13, and 24.1.10; one report also advises restricting exposed APIs.