Home/CVE/When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded
CVE
CVE-2026-3446
When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded
When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use "validate=True" to enable stricter processing of base64 data.
EPSS 0.00029
EPSS exploitation odds0.03% · top 91%
Monitor
- ⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)
No Sigma yet — build one →
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-3446, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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Severity & exploitation scoring
EPSS exploitation probability
0.03%
Top 91%odds of exploitation in the next 30 days
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Tech impact
partial
Lifecycle
- 10 Apr 2026Published to NVD
- 13 Apr 2026Last modified
Every entry is a recorded date - NVD publish/modify, CISA KEV add, public exploit disclosure. No inferred events.
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ATT&CK techniques
6Techniques this CVE enables - linked via CWE → CAPEC → ATT&CK. Pills with a solid outline are named directly in ATT&CK or Nuclei templates (high confidence); the others are linked through weakness mappings.
T1557.002 · ARP Cache Poisoning T1584.002 · DNS Server T1491 · Defacement T1211 · Exploitation for Stealth T1542.002 · Component Firmware T1556 · Modify Authentication Process
▤ Build a SIEM detection for these techniques
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CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-111 · JSON Hijacking (aka JavaScript Hijacking) CAPEC-CAPEC-141 · Cache Poisoning CAPEC-CAPEC-142 · DNS Cache Poisoning CAPEC-CAPEC-148 · Content Spoofing CAPEC-CAPEC-218 · Spoofing of UDDI/ebXML Messages CAPEC-CAPEC-384 · Application API Message Manipulation via Man-in-the-Middle CAPEC-CAPEC-385 · Transaction or Event Tampering via Application API Manipulation CAPEC-CAPEC-386 · Application API Navigation Remapping CAPEC-CAPEC-387 · Navigation Remapping To Propagate Malicious Content CAPEC-CAPEC-388 · Application API Button Hijacking CAPEC-CAPEC-665 · Exploitation of Thunderbolt Protection Flaws CAPEC-CAPEC-701 · Browser in the Middle (BiTM)
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Weakness Classification
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Related CVEs
4CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.
CVE-2013-7397
Async Http Client (aka AHC or async-http-client) before 1.9.0 skips X.509 certif...
same CWE-345
CVE-2013-7398
main/java/com/ning/http/client/AsyncHttpClientConfig.java in Async Http Client (...
same CWE-345
CVE-2013-2167
python-keystoneclient version 0.2.3 to 0.2.5 has middleware memcache signing byp...
same CWE-345
CRITICAL
CVE-2014-0364
The ParseRoster component in the Ignite Realtime Smack XMPP API before 4.0.0-rc1...
same CWE-345
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Vendor Advisories
13suse-csafSUSE-SU-2026:1937-1
suse-csafSUSE-SU-2026:1947-1
suse-csafSUSE-SU-2026:1818-1
suse-csafSUSE-SU-2026:1715-1
suse-csafopenSUSE-SU-2026:10667-1
suse-csafSUSE-SU-2026:21415-1
suse-csafSUSE-SU-2026:21447-1
suse-csafSUSE-SU-2026:1503-1
suse-csafopenSUSE-SU-2026:10579-1
suse-csafopenSUSE-SU-2026:10580-1
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References & Sources
6Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.