CVE-2026-88840: Busybox: busybox: tls ssl_server reads one byte out of bounds when parsing truncated clienthello
Noroxi assessment
Priority: Monitor (action score 21/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- According to the record, no fixed version is available yet.
Low priority for now. Update when a fix is released; follow the vendor's advisory.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
BusyBox TLS get_client_hello() reads past the end of the input buffer when parsing a truncated ClientHello message.
- Published
- Sep 23, 2026
- Updated
- Sep 26, 2026
- EPSS
- 0.2% · 10th percentile
- CWE
- CWE-125
Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · redhat
- 5.3
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
Red Hat Red Hat Hardened Images
- all versionsaffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:14 | busybox | from 0 | — |
Same product
red hat: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-90954Busybox: busybox: dpkg-deb extraction-root escape via per-ar-member deferred symlink flush31Monitor
- CVE-2026-96512Sudo: sudo: tz environment variable allows bypass of notbefore/notafter time-based authorization31Monitor
- CVE-2026-78410Util-linux: util-linux: restricted bind mounts do not pin the source, allowing x-mount.owner/group/mode redirection31Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-88837Sep 23, 2026 · Busybox: busybox: httpd misidentifies yescrypt password hashes as plaintext, inverting authentication26Monitor
- ← EarlierCVE-2026-88839Sep 23, 2026 · Busybox: busybox: passwd/group parser writes heap pointers out of bounds due to stale tokenize() endpoint26Monitor
- Later →CVE-2026-107444Oct 8, 2026 · Rubygem-katello: katello: katello: katello docker tags repositories api cross-organization authorization bypass17Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-888350 days apartBusybox: busybox: dpkg read_package_field() steps past nul terminator, causing out-of-bounds read on malformed .deb packages24Monitor
- CVE-2026-1500358 days apartBinutils: gnu binutils: heap-buffer-overflow in linker leads to information disclosure and denial of service22Monitor
- CVE-2026-436799 days apartLibxpm: libxpm: denial of service via out-of-bounds read in xpm file parsing22Monitor
- CVE-2026-8787514 days apartCups: openprinting cups: heap out-of-bounds read in cupsutf32toutf8() via missing source-length bound17Monitor
- CVE-2026-8549836 days apartPolkit: regression in cve-2026-4897 fix (polkit read_cookie()) - stack buffer underflow14Monitor
- CVE-2026-8884221 days apartBusybox: busybox: dpkg stale field_start pointer causes out-of-bounds read and status file corruption13Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
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Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.