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Limit http connections and add free heap check before allocating for SSL #9693

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Merged
thebentern merged 7 commits into from
Feb 21, 2026
Merged

Limit http connections and add free heap check before allocating for SSL #9693

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3f28c1a
Reduce maximum concurrent HTTPS connections to save memory
thebentern Feb 18, 2026
d5180b0
Add heap check and limit connections to prevent HTTPS connection rela…
thebentern Feb 19, 2026
6376db6
Merge branch 'master' into limit-https
thebentern Feb 19, 2026
9fd1943
Use Throttle::isWithinTimespanMs for overflow-safe heap warning throttle
thebentern Feb 21, 2026
c328fdc
Merge branch 'master' into limit-https
thebentern Feb 21, 2026
e979cbd
Update src/mesh/http/WebServer.cpp
thebentern Feb 21, 2026
aa267af
Fix double-free heap corruption and parser leak in web server handlers
thebentern Feb 21, 2026
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25 changes: 22 additions & 3 deletions src/mesh/http/WebServer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include <HTTPBodyParser.hpp>
#include <HTTPMultipartBodyParser.hpp>
#include <HTTPURLEncodedBodyParser.hpp>
#include <Throttle.h>
#include <WebServer.h>
#include <WiFi.h>

Expand Down Expand Up @@ -55,6 +56,12 @@ static const int32_t ACTIVE_INTERVAL_MS = 50;
static const int32_t MEDIUM_INTERVAL_MS = 200;
static const int32_t IDLE_INTERVAL_MS = 1000;

// Maximum concurrent HTTPS connections (reduced from default 4 to save memory)
static const uint8_t MAX_HTTPS_CONNECTIONS = 2;

// Minimum free heap required for SSL handshake (~40KB for mbedTLS contexts)
static const uint32_t MIN_HEAP_FOR_SSL = 40000;

static SSLCert *cert;
static HTTPSServer *secureServer;
static HTTPServer *insecureServer;
Expand All @@ -67,8 +74,20 @@ static void handleWebResponse()
if (isWifiAvailable()) {

if (isWebServerReady) {
if (secureServer)
secureServer->loop();
// Check heap before HTTPS processing - SSL requires significant memory
if (secureServer) {
uint32_t freeHeap = ESP.getFreeHeap();
if (freeHeap >= MIN_HEAP_FOR_SSL) {
secureServer->loop();
} else {
// Skip HTTPS when memory is low to prevent SSL setup failures
static uint32_t lastHeapWarning = 0;
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if (!Throttle::isWithinTimespanMs(lastHeapWarning, 30000)) {
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LOG_WARN("Low heap (%u bytes), skipping HTTPS processing", freeHeap);
lastHeapWarning = millis();
}
}
}
insecureServer->loop();
}
}
Expand Down Expand Up @@ -229,7 +248,7 @@ void initWebServer()
LOG_DEBUG("Init Web Server");

// We can now use the new certificate to setup our server as usual.
secureServer = new HTTPSServer(cert);
secureServer = new HTTPSServer(cert, 443, MAX_HTTPS_CONNECTIONS);
insecureServer = new HTTPServer();

registerHandlers(insecureServer, secureServer);
Expand Down
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