7-Zip UEFI Capsule (.scap) Uninitialized Heap Memory Disclosure
CVE-2026-48101 is an uninitialized memory disclosure vulnerability in 7-Zip's UEFI capsule (.scap) parser affecting versions 9.21 through 26.00. In the vulnerable code path, the OpenCapsule function allocates a heap buffer sized according to the attacker-controlled CapsuleImageSize field, up to 1 GiB, without zero-initializing the allocation. It then attempts to read file contents into that buffer using ReadStream_FALSE, but the return value is ignored. If a crafted .scap file is truncated, the unread portion of the heap buffer remains filled with uninitialized heap data. That residual memory is subsequently exposed as extracted file content through GetStream, resulting in disclosure of process heap contents to the attacker or user handling the malicious archive.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
2 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.