Guest access to Firecracker process memory after a failed memory discard
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 1.16.2
- Who is exposed
- Specific setups only
Do first: Upgrade to a fixed version: 1.16.2.
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure5/25Specific setups only
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 63 if added to CISA KEV
- Would score about 58 if CISA's SSVC rates exploitation active
- Would score about 23 if CISA's SSVC rates it automatable
CVE-2026-122192 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects firecracker; fixed in 1.16.2.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 13/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 1.16.2
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Firecracker, the virtual machine monitor used to run lightweight microVMs, is affected by a flaw in how it handles a failed memory remap during balloon or virtio-mem discard requests. An attacker who already has root privileges inside a guest VM on a microVM restored from a snapshot with the File memory backend can read or modify the Firecracker process memory, but only locally and with high-privilege access required, and the bug is triggered only if the host fails to create the replacement mapping.
Read the original description
Improper handling of a failed memory remap in Firecracker versions 0.23.0 through 1.16.1 might allow a guest user with root privileges to read or modify Firecracker VMM process memory via balloon or virtio-mem discard requests on microVMs restored from a snapshot with the File memory backend, if the host fails to create the replacement mapping. To remediate this issue, users should upgrade to Firecracker 1.16.2 or 1.17.0 and later.
What to do
Upgrade to a fixed version: 1.16.2.
Workaround: Restore snapshots using the Uffd memory backend instead of the File backend.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- AWS firecracker
From 0.23.0 · fixed in 1.16.2
Evidence 4
- Advisory
- Advisory
- Patch
- Patch
Corrections
None so far.
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Questions about CVE-2026-122192
Is CVE-2026-122192 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-122192?
firecracker: from 0.23.0 before 1.16.2.Source: cve.now feed data
How do I fix CVE-2026-122192?
Move to Firecracker 1.16.2 or later, which is the fixed version in the affected range. Until then, restore snapshots using the Uffd memory backend, following its documented requirements for handling discarded pages.Source: aws.amazon.com