CVE-2026-5503Disclosure(wolfssl / wolfssl)

LOWCVSS 9.1 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

In TLSX_EchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSX_Find returned NULL. This caused TLSX_UseSNI to attach the attacker-controlled publicName to the shared WOLFSSL_CTX when no inner SNI was configured. TLSX_EchRestoreSNI then failed to clean it up because its removal was gated on serverNameX != NULL. The inner ClientHello was sized before the pollution but written after it, causing TLSX_SNI_Write to memcpy 255 bytes past the allocation boundary.

wolfssl CVEs Back to dashboard

0.0/ 10 priority

Sources & remediation

Other references

https://github.com/wolfSSL/wolfssl/pull/10102

Weakness type (CWE)

CWE-787

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

wolfssl

Threat summary

3 mentions across 2 observed days
Momentum state: stable

What's happening

Technical details provided in 3 signals
Disclosure: 3 classified signals
Peaked 1d ago at 2 mentions (2026-04-09); latest day: 1
3 total mentions across 2 days

Affected systems

Vendors

wolfssl

Products

wolfssl

Deep dive

Activity timeline3 mentions / 2d

Signal classification1 categories

Disclosure

3100.0%

Referenced assets4 URLs

By indicator

Classification over time

Date	Total	Labels

2026-04-09	2	Disclosure2
2026-04-14	1	Disclosure1

Full discourse3 posts

Vulmon Vulnerability Feed@VulmonFeeds177d
Disclosure
CVE-2026-5503 Buffer Overflow in WolfSSL ECH SNI Handling via Attacker-Controlled Exten... https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-5503 Vulnerability Notification: https://alerts.vulmon.com/?utm_source=twitter&utm_medium=social&utm_campaign=2102281&utm_content=3
Post summary
The content serves as a brief notification of CVE-2026-5503, describing a buffer overflow in WolfSSL, but offers no PoC, exploit, or patch details.
0000053
4.0K followersView on X
Infoflowcloud@infoflowcloud181d
Disclosure
🚨*CVE* CVE-2026-5503 In TLSX_EchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSX_Find returned NULL. This caused TLSX_UseSNI to attach the attacker-contro… https://www.cve.org/CVERecord?id=CVE-2026-5503 ----- Traducción: CVE-2026-5503 En … http://infoflow.cloud`
Post summary
The snippet announces CVE-2026-5503, describing a code path that incorrectly processes TLSX extensions, but it contains no proof‑of‑concept, exploit code, or patch information.
0000028
67 followersView on X
CVE@CVEnew181d
Disclosure
CVE-2026-5503 In TLSX_EchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSX_Find returned NULL. This caused TLSX_UseSNI to attach the attacker-contro… https://www.cve.org/CVERecord?id=CVE-2026-5503
Post summary
The message announces CVE-2026-5503, outlining an OpenSSL TLS extension handling flaw that can be exploited to inject attacker‑controlled data; no evidence of exploitation or mitigation is provided.
00000247
57.0K followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	wolfssl	wolfssl	-	-	-

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