Answer in brief
CVE-2026-42505 records a Medium severity (CVSS 5.3) vulnerability in Invoking Encrypted Client Hello privacy leak in crypto/tls. The current sources do not mark it as known exploited. The current feed maps Go standard library/crypto/tls (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Go standard library/crypto/tls (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Go standard library/crypto/tlsgeneric | >=0 <1.25.12 || >=1.26.0-0 <1.26.5 || >=1.27.0-0 <1.27.0-rc.2 | 1.25.12, 1.26.5, 1.27.0-rc.2 |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 8, 2026
Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-42505 records a Medium severity (CVSS 5.3) vulnerability in Invoking Encrypted Client Hello privacy leak in crypto/tls. The current sources do not mark it as known exploited. The current feed maps Go standard library/crypto/tls (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Go standard library/crypto/tls (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Go standard library/crypto/tlsgeneric | >=0 <1.25.12 || >=1.26.0-0 <1.26.5 || >=1.27.0-0 <1.27.0-rc.2 | 1.25.12, 1.26.5, 1.27.0-rc.2 |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 8, 2026
Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.
Quoted source text, attributed separately from HOL analysis.