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NVD / CVE Program· CNA mitre

CVE-2020-35471: Envoy before 1.16.1 mishandles dropped and truncated datagrams, as demonstrated by a segmentation fault for a UDP packet size larger than…

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 2.3% (FIRST EPSS); higher than 84.2% of all records.
  • 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.
  • Fixed version: envoy-proxy (openSUSE:Leap 15.3) 1.14.6-bp153.3.4.1; envoy-proxy (SUSE:Package Hub 15 SP3) 1.14.6-bp153.3.4.1.

Low priority for now. Upgrade to envoy-proxy (openSUSE:Leap 15.3) 1.14.6-bp153.3.4.1; envoy-proxy (SUSE:Package Hub 15 SP3) 1.14.6-bp153.3.4.1 or later.

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

Envoy before 1.16.1 mishandles dropped and truncated datagrams, as demonstrated by a segmentation fault for a UDP packet size larger than 1500.

Published
Dec 14, 2020
Updated
Jun 16, 2026
EPSS
2.3% · 84th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.3%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
envoyproxyenvoy

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • envoyproxy envoybefore 1.16.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
openSUSE:Leap 15.3envoy-proxybefore 1.14.6-bp153.3.4.11.14.6-bp153.3.4.1
SUSE:Package Hub 15 SP3envoy-proxybefore 1.14.6-bp153.3.4.11.14.6-bp153.3.4.1

Same product

envoyproxy: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-30255HTTP/2: CPU exhaustion due to CONTINUATION frame flood
    56Plan
  • CVE-2024-27919HTTP/2: memory exhaustion due to CONTINUATION frame flood
    55Plan
  • CVE-2021-29492Bypass of path matching rules using escaped slash characters
    52Plan

Published before and after this one in the same product

  • ← EarlierCVE-2020-25018Oct 1, 2020 · Envoy master between 2d69e30 and 3b5acb2 may fail to parse request URL that requires host canonicalization.
    30Monitor
  • ← EarlierCVE-2020-35470Dec 14, 2020 · Envoy before 1.16.1 logs an incorrect downstream address because it considers only the directly connected peer, not the information in the…
    35Monitor
  • Later →CVE-2021-21378Mar 10, 2021 · JWT authentication bypass with unknown issuer token
    33Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
opensuse:envoy-proxy1.14.6-bp153.3.4.1 · openSUSE:Leap 15.3Package registry (OSV)
suse:envoy-proxy1.14.6-bp153.3.4.1 · SUSE:Package Hub 15 SP3Package registry (OSV)

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.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

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
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records