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CVE-2026-47775· NVD / CVE Program· CNA GitHub_M

Envoy OAuth2 Filter: Padding Oracle via AES-256-CBC Cookie Decryption

Noroxi assessment

Priority: Monitor (action score 27/100)

  • 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: 0.21% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • Fixed version: envoyproxy envoy 1.35.11.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to envoyproxy envoy 1.35.11 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 is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, the OAuth2 HTTP filter's encrypt()/decrypt() functions use AES-256-CBC without an authentication tag (no HMAC, no AEAD). The /callback endpoint returns HTTP 302 on successful decryption and HTTP 401 on padding failure, creating a padding oracle. An attacker who obtains the encrypted CodeVerifier cookie can recover the plaintext PKCE code_verifier in ~6,200 requests (~100 seconds), then exchange it with a stolen authorization code to obtain the victim's access token. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

MediumCVSS 6.8 · v3.1—No exploit Fix available
Published
Jun 26, 2026
Updated
Jun 29, 2026
EPSS
0.2% · 11th percentile

Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
27 / 40 · 6.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.8
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
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • 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 envoy1.35.0 and later · before 1.35.11
  • envoyproxy envoy1.36.0 and later · before 1.36.7
  • envoyproxy envoy1.37.0 and later · before 1.37.3
  • envoyproxy envoy1.38.0 and later · before 1.38.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • envoyproxy envoy

    • >= 1.38.0, < 1.38.1, >= 1.37.0, < 1.37.3, >= 1.36.0, < 1.36.7, < 1.35.11affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
openSUSE:Tumbleweedistioctlbefore 1.30.2-1.11.30.2-1.1

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
    56Plan
  • CVE-2021-29492Bypass of path matching rules using escaped slash characters
    53Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-47221Jun 26, 2026 · Envoy: Null pointer deref in internal redirects
    30Monitor
  • ← EarlierCVE-2026-47692Jun 26, 2026 · Envoy: PROXY Protocol v2 header generator emits "skipped" TLVs, causing 65 KB attacker-controlled spillover into the upstream application stream
    17Monitor
  • Later →CVE-2026-47778Jun 26, 2026 · Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)
    17Monitor

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
envoyproxy envoy1.35.11 · descriptionVendor (CNA)
opensuse:istioctl1.30.2-1.1 · openSUSE:TumbleweedPackage 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.

EPSS, last 120 days

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 researchers

Finders, 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.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-209 · Generation of Error Message Containing Sensitive Information

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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