wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies, so oversized writes succeed instead of trapping. A malicious guest can pass large buffers to write on outgoing-body resources, holding host allocations for the store's lifetime and exhausting host memory.
CVE-2026-115388
MEDIUMPre-NVD 6.26.2Trending — 3 sources updated this week
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 6.2 from GitHub Security Advisory published 2026-10-22. A secondary CVSS source baseline 6.2; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Also known asEUVD-2026-108318 (ENISA EUVD) · GHSA-7qg7-h7wh-p6q8 (GitHub Security Advisories)Source: ENISA EUVD
6.2EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 6.2Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 6.2
- EG Score
- 6.2MEDIUMhigh confidence
- EG Risk
- 28EG Risk 28/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity62% × 45%Impact severity (EG Severity): CVSS 6.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.1% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.1%
- EPSS %ILE
- 1st
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (6.2): severity, escalated by confirmed exploitation. This CVE's 6.2 is its impact severity (EG Severity), not escalated.
- EG Severity
- 6.2 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 22, 2026
Last Modified
October 29, 2026
Advisory Details (2)
Auto-updated Oct 22, 2026Patch available. Sources: github.
Web page
Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Memory Exhaustion DoS via wasmtime-wasi-http Outgoing Body Write | Advisories | VulnCheck
https://www.vulncheck.com/advisories/wasmtime-before-36.0.16-37.0.0-before-48.0.3-and-49.0.0-before-49.0.1-memory-exhaustion-dos-via-wasmtime-wasi-http-outgoing-body-writeGitHub advisoryMentions a patch (unverified)
wasmtime-wasi-http: outgoing HTTP body write allows guest-driven host memory exhaustion (DoS) · Advisory · bytecodealliance/wasmtime · GitHub
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-c9gc-w9vx-w86pVendor Advisories for CVE-2026-115388(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
crates.io(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| wasmtime-wasi-http | — | 49.0.1 (one range) | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 17× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-29 04:29 UTCEG score recompute
- 2026-10-29 04:29 UTCGHSA enrichmentGHSA-7qg7-h7wh-p6q8 · GitHub CVSS 6.2
- 2026-10-29 02:37 UTCEG score recompute
- 2026-10-29 02:37 UTCGHSA enrichmentGHSA-7qg7-h7wh-p6q8 · GitHub CVSS 6.2
- 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-25 14:50 UTCEG score recompute
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-22 19:28 UTCEG score recompute
- 2026-10-22 19:16 UTCEG score recomputeFirst assessed: 6.2 MEDIUM
- 2026-10-22 19:15 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Frequently asked(5)
What is CVE-2026-115388?
CVE-2026-115388 is a medium-severity vulnerability; its CVE record was published on October 22, 2026. wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies, so oversized writes succeed instead of trapping. A malicious guest can pass large buffers to write on…
When was CVE-2026-115388 made public?
CVE-2026-115388 was made public on September 24, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on October 22, 2026. EchelonGraph's copy of the record carries a last-modified date of October 29, 2026; the record at its source may have been updated since.
Is CVE-2026-115388 actively exploited?
CVE-2026-115388 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-115388?
CVE-2026-115388 has a CVSS base score of 6.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-115388?
A fix for CVE-2026-115388 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-115388 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-115388
Is Your Infrastructure Affected by CVE-2026-115388?
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